I'd say that there is not a divergence of opinion here; but a divergence of preference. What frogman said yesterday triggered a memory. I was listening to a 70s vintage record a few months ago and remember thinking to myself that the reverb was not nearly as apparent as it was years ago on my old system with the speakers that had 20-20k response. This record is a studio recording and the reverb from the walls is very apparent. On my old system it was nearly at a level of distraction. I remember my brother listening to that record years ago and commenting on it and he didn't like it. I could still hear the reverb a bit but much more subtle on today's system. Another observation: In the services yesterday morning a musician was playing the drums. Not real drums, they were electronic. The loud low frequency thumping created a pressure in my head. I didn't really enjoy that part of the music.
I used to do NVH (Noise Vibration Harshness) work in automotive in the 90s. I remember back then a course instructor at an SAE seminar said that older people do not like low frequencies but young people do not mind them so much. When gas prices started rising and cars started shrinking, the stiffness of chassis went down. Late 70s to late 80s saw a trend away from body on frame moving towards unibody for weight savings and better fuel economy. The NVH of cars worsened. I think cars made in the 50s and 60s rode quieter than 70s and 80s cars if compared as new to new. Boom was prevalent in unibody cars. Remember one design solution? They added speed sensitive volume to radios. By the early 90s automakers started using better steels, weld joint designs and stamped in patterns to increase body stiffness. They also added constrained layer damping materials and e-coat to reduce Boom and rattles. But I remember what that instructor said and I think I have reached that point where I don't really want the low, low frequency material at the same comparative loudness as mid bass and mid tones.
That what I was saying before- many people love their Maggies and Quads for their mid range magic and don't mind not having the bottom register. |
06-23-12: Stringreen
>Richard himself helped me with my setup and told me that the goal was NOT to get a flat frequency response...just s pleasing one.
That's an over-simplification.
As an engineer I have built speakers with acoustically small drivers and baffle sizes decreasing with frequency for a flatter first derivative of amplitude with respect to frequency off-axis.
Richard does the same, spending more on labor than he would with rectangular cabinets and then wraps the result with a cosmetic grill-frame producing more conventional aesthetics he can sell.
I can't come up with technical reasons for him to do that apart from the same pursuit of measurable "flatness" whether he quantifies it like that or the result just sounds better.
>Flat frequency response is a-musical.
That's wrong.
Your brain is looking for flat response in the direct sound with less high frequency content in the reflections. That's what you get from live un-amplified performances in good venues which should be the reference for sound reproduction. Any more real would be surreal.
When you feed such ideal signals to a SPL meter it doesn't look at the time domain and just averages everything together. It will and should show a roll-off towards high frequencies. It also picks up wiggles from combing which are often not perceptually important.
Trying to correct what the meter sees can ruin the things the speaker is doing right.
Amplitude adjustments around directivity minima can make things subjectively more natural and flatter (the BBC dip), although simple measurements may not show that's what's happening. |
06-22-12: Onhwy61
>I think Frogman is correct, but it should be put into perspective. Suppose you were an audiophile with limited funds. Would you be better off pursuing bass response down to 20Hz, or compromise at 50Hz (with room reinforcement) and put more money into going for a better quality midrange and treble? Unless you're an absolute bass fanatic the answer is self-evident.
The answer is counter-intuitive and not at all self-evident without a far better understanding of acoustics and psychoacoustics than the average audiophile's. The combination of physics and consumer market expectations make getting quality midrange without last octave extension unlikely so seeking good high frequency performance means looking for the same things that give you lower bass.
Beyond a room's Schroeder frequency (100 - 200 Hz in typical domestic rooms) and assuming the speaker is correctly voiced for your chosen placement with respect to room boundaries how natural a speaker sounds comes almost entirely from
1. Its polar response with the ideal being flat on-axis with directivity increasing monotonically with frequency. Our brain determines timbre from the spectra of what it believes to be a direct sound and its delayed reflections. An increase in reflected high frequency energy isn't consistent with natural sources (directivity increases with frequency) and environments (natural materials like foliage absorb and diffuse more at high frequencies where they're becoming acoustically large) it doesn't sound right.
This comes predominantly from the driver/baffle sizes/shapes you use including options to increase directivity from an acoustically small driver with a wave guide or cancellation from acoustic dipoles and cardioids.
Untamed driver and cabinet resonances can also play a negative role, showing up as amplitude peaks at all angles.
2. The distortions which go with approaching and exceeding a driver's linear limits. Harmonic distortions change the timbre and IM distortion adds non-musical sounds that weren't in the recording and damage the midrange.
Unfortunately you can't build a flat baffle 2-way with conventional cone and dome drivers which does well in both areas. When you compromise with a smaller mid-range to get better polar response you lack the displacement needed for clean reproduction of lower frequencies (250Hz is probably a nice lower limit for a 4" driver, 150 Hz 5", 120Hz 6-7", 80Hz 8.5", 40Hz 10"). When you compromise with a larger midrange to get clean output at acceptable listening levels you end up with a noticeable harshness resulting from the significantly broader dispersion crossing to the tweeter at 2-4KHz or beyond. People work around that with some success using a drop in output in the range (the BBC dip) although the resulting speaker is more sensitive to the room (you'll notice the lack of energy in a large/absorbing room because there's less compensation for the on-axis dip) than a speaker built with more uniform directivity.
Sticking to flat-baffled vaguely box-shaped speakers that most consumers shop for the solution is at least a 3-way, whether in one cabinet or separate boxes. 100-120Hz works well crossing to stereo "sub-woofers" which are better described as woofers, although if terms like "pole", "zero", and "biquad" aren't in your vocabulary that probably won't end well as a DIY exercise.
Once you do that the extra extension has negligible additional parts cost, although it costs you 9dB of efficiency for the same cabinet size or a box 8X as big at the same efficiency. Most consumer speaker company marketing departments compromise with lower bass to satisfy more listeners, smaller cabinets for spouses, and less efficiency.
The intuitive but incorrect counter-argument is that you're better off with fewer more expensive drivers. It fails because a pair of drivers in a conventional configuration have audible and measurable problems from their inherent physics that more appropriate sized less expensive drivers with lower total cost (and better sound) do not.
Whether you're spending $200, $2000, or $40,000 on drivers flatter on-axis and more monotonic polar response sound more similar than different. Deviating from that design goal is not good although the specific failings vary. It's like Tolstoy's comment "Happy families are all alike; every unhappy family is unhappy in its own way." |
06-22-12: Onhwy61
>I think Frogman is correct, but it should be put into perspective. Suppose you were an audiophile with limited funds. Would you be better off pursuing bass response down to 20Hz, or compromise at 50Hz (with room reinforcement) and put more money into going for a better quality midrange and treble? Unless you're an absolute bass fanatic the answer is self-evident.
The answer is counter-intuitive and not at all self-evident without a far better understanding of acoustics and psychoacoustics than the average audiophile's. The combination of physics and consumer market expectations make getting quality midrange without last octave extension unlikely so seeking good high frequency performance means looking for the same things that give you lower bass.
Beyond a room's Schroeder frequency (100 - 200 Hz in typical domestic rooms) and assuming the speaker is correctly voiced for your chosen placement with respect to room boundaries how natural a speaker sounds comes almost entirely from
1. Its polar response with the ideal being flat on-axis with directivity increasing monotonically with frequency. Our brain determines timbre from the spectra of what it believes to be a direct sound and its delayed reflections. An increase in reflected high frequency energy isn't consistent with natural sources (directivity increases with frequency) and environments (natural materials like foliage absorb and diffuse more at high frequencies where they're becoming acoustically large) and doesn't sound right.
This comes predominantly from the driver/baffle sizes/shapes you use including options to increase directivity from an acoustically small driver with a wave guide or cancellation from acoustic dipoles and cardioids.
Untamed driver and cabinet resonances can also play a negative role, showing up as amplitude peaks at all angles.
2. The distortions which go with approaching and exceeding a driver's linear limits. Harmonic distortions change the timbre and IM distortion adds non-musical sounds that weren't in the recording and damage the midrange.
Unfortunately you can't build a flat baffle 2-way with conventional cone and dome drivers which does well in both areas. When you compromise with a smaller mid-range to get better polar response you lack the displacement needed for clean reproduction of lower frequencies (250Hz is probably a nice lower limit for a 4" driver, 150 Hz 5", 120Hz 6-7", 80Hz 8.5", 40Hz 10"). When you compromise with a larger midrange to get clean output at acceptable listening levels you end up with a noticeable harshness resulting from the significantly broader dispersion crossing to the tweeter at 2-4KHz or beyond. People work around that with some success using a drop in output in the range (the BBC dip) although the resulting speaker is more sensitive to the room (you'll notice the lack of energy in a large/absorbing room because there's less compensation for the on-axis dip) than a speaker built with more uniform directivity.
Sticking to flat-baffled vaguely box-shaped speakers that most consumers shop for the solution is at least a 3-way, whether in one cabinet or separate boxes. 120Hz and beyond can work well crossing to stereo "sub-woofers" which are better described as woofers, although if terms like "pole", "zero", and "biquad" aren't in your vocabulary that probably won't end well as a DIY exercise.
Once you do that the extra extension has negligible additional parts cost, although it costs you 9dB of efficiency for the same cabinet size or a box 8X as big at the same efficiency. Most consumer speaker company marketing departments compromise with lower bass to satisfy more listeners, smaller cabinets for spouses, and less efficiency.
The intuitive but incorrect counter-argument is that you're better off with fewer more expensive drivers. It fails because a pair of drivers in a conventional configuration have audible and measurable problems from their inherent physics that more appropriate sized less expensive drivers with lower total cost (and better sound) do not.
Whether you're spending $200, $2000, or $40,000 on drivers flatter on-axis and more monotonic polar response sound more similar than different. Deviating from that design goal is not good although the specific failings vary. It's like Tolstoy's comment "Happy families are all alike; every unhappy family is unhappy in its own way." |
One of the things that bothered me most about early digital recordings (actually, until very recently) was not the harshness, brightness or grain, it was the very obvious (to me) sense that there was a frequency extension ceiling above the music; that the upper harmonic extension simply came to a screeching halt; technically speaking, around 21KHz. Some would argue that we can't hear above that range. Well we can argue that one forever, but wether it is the absence of harmonics above that range, or the effect that this absence has on lower audible frequencies doesn't matter, it is audible either way. I hear a similar effect at the bottom end of the spectrum. Wether it is the ambience cues that we hear/sense, or undertones, or whatever, when the speaker is incapable of reaching into the lowest octave there is an audible low frequency ceiling (floor?), where just as with the high frequency ceiling, things come to a halt and one hears/senses the absence of limitless extension even if there is no musical content in that frequency range. All this compared to the sound of live music, of course; not just in a hall, but also what one hears in a studio. |
You are right. Full spectrum audio is achievable but takes a lot of patience and money. More than I have of either one. I certainly don't want to discourage the enthusiasts that are working to achieve that, but it is also good to share our failures and successes so others learn something from it. I'm pretty happy where I am with my system today. I think my large size and volume listening room combined with the wood floors made a tremendous improvement in the sound of the lower registers. I had the Thiel CS3.6 pair when I moved into this house and they just didn't seem to be enough for this large room. When I got the CS6 pair the sound filled in nicely. I'm not trying to play at loud volumes, just that the larger speakers seem to fill the range better in a larger room. The converse is true too- smaller speakers work better in a smaller room.
Everyone has a different path to take in this hobby. Many are happy to have the mid-range magic of Quads, which I also used to enjoy immensely at a friend's house years ago with female vocals, and others want the full range to go with their broad stage orchestral music and others the hard kick and punch of rock and roll. |
06-23-12: Tonywinsc
Johnnyb, you explained it well. It takes a lot of effort and work to get it balanced across the broad spectrum. ... Like you said, you have to work very hard to balance all of that out and get it to work. You are taking great pains to get the reflections and the sources to all come together at the listening position. I still doubt you can achieve a balanced 20-20k in a small room.
Sorry; I have a nasty virus right now that's got me grumpy. You've been gracious and make good points. An advantage of the stand mount/subwoofer approach is that if you have to put your system in a smaller room you can dial back the subwoofer(s). Even a JL Gotham G213 can be turned down to reasonable levels in a small room, but you can't do that with a pair of Wilson Alexandrias (or other passive large full-range speakers) which will inevitably overload a small room. |
My Vandersteen 5A's have a bunch of pots in the back that adjusts frequencys from the very low bass to the midbass. Richard himself helped me with my setup and told me that the goal was NOT to get a flat frequency response...just s pleasing one. Flat frequency response is a-musical. |
Johnnyb, you explained it well. It takes a lot of effort and work to get it balanced across the broad spectrum. What I was trying to say is that the long wavelengths are multiple times the length of a typical listening position. So the SPL at 12ft (typical listening position) of a 20Hz frequency is going to be much lower that at 56.5 ft-, ie. the full wavelength. So to make the 20Hz frequency the same loudness at 12ft as shorter wavelengths will take a lot of power and then the loudness of the 20Hz frequency will be much higher as you move out to the 56ft range. Like you said, you have to work very hard to balance all of that out and get it to work. You are taking great pains to get the reflections and the sources to all come together at the listening position. I still doubt you can achieve a balanced 20-20k in a small room. |
06-23-12: Tonywinsc
If you think you can just buy a subwoofer, drop it into your living room and add an octave to the range of your music, then you are deluding yourselves.
Why do I bother qualifying my statements with phrases like "properly blended" in my posts if you bulldoze over them like I never said anything at all. It's not like placement of a 350-lb. pair of full-range speakers with spikes is a piece of cake either. OF COURSE you have to take special care in placement, phase adjustment, crossover adjustment, and level adjustment. Who on this forum wouldn't know that? I've seamlessly incorporated seven subwoofers into various systems in the past 7 years. I had a pair of subs in my living room and after living with them a few months, took about 4 hours to reposition them and re-adjust their settings. It was well worth it. I can now play large scale orchestral works (Berlioz, anyone?) on this system with engaging and credible reproduction. Blending subs is a pain in the ass that can take anywhere from 2-4 hours to several days. But if it saves you $5K or more compared to the equivalent passive full range speaker, it's easily worth it. As for the wavelength argument, my small towers are in an open architecture living room. There's almost no limit to how long a soundwave can form in my house interior--across the LR, up the stairs and down the hall, or across the living room, down the stairs, and out to the 18x22 media room. Here's another thought: regardless of the size of the venue, if you have a subwoofer putting out a 25 Hz frequency, even if you're sitting well within the fully formed wavelength, the frequency is hitting your eardrums (and flapping your pantsleg) 25 times per second, and your brain will perceive it as such. By your argument we couldn't hear bass below 180 Hz (about F below middle C) from a car stereo where the maximum interior dimension is around six feet.. Psst... we can. |
If you think you can just buy a subwoofer, drop it into your living room and add an octave to the range of your music, then you are deluding yourselves. Room volume and size plays a much greater role in the low frequency response of a stereo system than with the higher voice range frequencies. Just like discussed, speakers can have a perfectly flat frequency response in an ideal anechoic environment, they do not quite achieve that flat response line in a real world listening environment. Perfectly flat response is a bit dull and boring anyway. I know, I tried that once years ago. I worked hard on my room with an analyzer and anechoic panels to make a flat response at my listening position. It sucked the life out of the music. btw- I had speakers back then had a 20-20k Hz range. I found the bass sounded better way into the next room as compared to my listening position.
When you add a subwoofer to your system and things seem to go deeper, that's mostly because it is reinforcing the 30-40's Hz range. You are not going to hear 20Hz from 12 ft back, ie. not at the same SPL level as the higher frequencies. That wavelength is over 56 feet long. Sure you can fold it over and reflect it back, but you better have some sturdy walls to get efficient reflections and the distances better be just right so it is at the correct phase angle at your ears. Even the 30-40 Hz range have wavelengths over 20ft long so their SPL levels at 12 ft back are not going to be as high as levels in the voice range without some boosting. Just try listening to the grand pipe organ from 12 feet back sometime. You won't hear the low pedals that close to the pipes nearly like being much further back in the building. |
06-22-12: Onhwy61
I think Frogman is correct, but it should be put into perspective. Suppose you were an audiophile with limited funds. Would you be better off pursuing bass response down to 20Hz, or compromise at 50Hz (with room reinforcement) and put more money into going for a better quality midrange and treble? Unless you're an absolute bass fanatic the answer is self-evident.
It's only "self-evident" to those eager to sacrifice an octave of the music for a little extra refinement. Actually, different music-loving audiophiles split up their priorities and budgets in different ways, and full range frequency response is one of them. All the imaging and transparency in the world can get annoying over time if a conspicuous part of the pitch spectrum is missing. I think there's a strong case to be made for making a pair of powered subwoofers part of a speaker budget. Not because I'm a bass freak, but because it may be a smarter way to split up the frequency range--and the money. These days there are some stupendous stand-mounted speakers at $3K or less, with transparency, excellent dispersion and therefore uniform power response, treble extension, soundstage and especially pinpoint imaging. At some point when you build a passive loudspeaker system and you go for full range, a lot of the money is spent on cabinet rigidity and damping to keep the big woofer from smearing the rest of the sound emanating from the higher drivers. With separate subs it's easier to retain the transparency and imaging of the mini-monitor while adding a low frequency foundation that does not cost too much on one hand and doesn't smear the rest of the sound on the other. How many of us have heard a line of speakers where the stand-mounted unit sounded the best while the floorstanding version lost some of the magic just to get another 1/2 octave of bass extension? With separate powered subs you get to retain the magic while adding the foundation. You also have the option of placing the subwoofers where they mate best with the room. How many times do we move full range speakers around, finding that one spot gives the best midrange/imaging/soundstage but another provides the best bass? It's pretty typical. Separate subs fix that, and you don't have to be a bass freak to appreciate it. Also, it's more cost-effective. You could get a pair of Cirrus Vapors with the external crossover option, stands, and a pair of JL F112 subs for at least $5K less than a pair of Wilson Sophias. You'd get all that midrange transparency and treble extension of the ribbons, plus inner detail owing to the Herculean bracing and cabinet damping of the Vapors, plus the slam and dynamics of the JL powered subwoofers. The total package is cheaper because you don't have to damp and brace the monitor cabinets to keep deep bass waves under control--they're in a separate box. |
How did that happen? The Audiogon gremlins strike again. I didn't resubmit that post. Nonetheless, sorry. |
****If the article is correct, only wind and string instrument can create undertone. ****
Yes, and we all know how authoritative Wikepedia is. And no, not just those instruments can create undertones.
The Wikepedia article is (as usual) very incomplete. The production of undertones does not require special playing techniques. They can (and are) be produced by the acoustic interactions of two or more fundamentals. In the example that I described, no special techniques were
needed nor used. Undertones occur naturally as part of the harmonic texture of music. They add timbral complexity to music.
****I tend to agree that below 30Hz is not really musically relavant. ****
Really?
****Sure, it adds ambience in some cases. By the low 20s it is more felt than heard. It is an awesome experience to hear a large pipe organ in a large cathedral. I have never heard that reproduced electronically 100%.
Perhaps it would take a room nearly as big as a cathedral to do it. The 16ft pedal on the pipe organ just makes a pressure and creates a certain mood and is always a relief when that low frequency sound ends. I think that is part of the mood too. I think some experiences like being in front of a large pipe organ need to be experienced first hand.****
Sounds like musical relevance to me. Below 30hz reproduction may not be absolutely necessary, but it is clearly relevant and adds a great deal. |
|
I think Frogman is correct, but it should be put into perspective. Suppose you were an audiophile with limited funds. Would you be better off pursuing bass response down to 20Hz, or compromise at 50Hz (with room reinforcement) and put more money into going for a better quality midrange and treble? Unless you're an absolute bass fanatic the answer is self-evident. |
****If the article is correct, only wind and string instrument can create undertone. ****
Yes, and we all know how authoritative Wikepedia is. And no, not just those instruments can create undertones.
The Wikepedia article is (as usual) very incomplete. The production of undertones does not require special playing techniques. They can (and are) be produced by the acoustic interactions of two or more fundamentals. In the example that I described, no special techniques were
needed nor used. Undertones occur naturally as part of the harmonic texture of music. They add timbral complexity to music.
****I tend to agree that below 30Hz is not really musically relavant. ****
Really?
****Sure, it adds ambience in some cases. By the low 20s it is more felt than heard. It is an awesome experience to hear a large pipe organ in a large cathedral. I have never heard that reproduced electronically 100%.
Perhaps it would take a room nearly as big as a cathedral to do it. The 16ft pedal on the pipe organ just makes a pressure and creates a certain mood and is always a relief when that low frequency sound ends. I think that is part of the mood too. I think some experiences like being in front of a large pipe organ need to be experienced first hand.****
Sounds like musical relevance to me. Below 30hz reproduction may not be absolutely necessary, but it is clearly relevant and adds a great deal. |
I tend to agree that below 30Hz is not really musically relavant. Sure, it adds ambience in some cases. By the low 20s it is more felt than heard. It is an awesome experience to hear a large pipe organ in a large cathedral. I have never heard that reproduced electronically 100%. Perhaps it would take a room nearly as big as a cathedral to do it. The 16ft pedal on the pipe organ just makes a pressure and creates a certain mood and is always a relief when that low frequency sound ends. I think that is part of the mood too. I think some experiences like being in front of a large pipe organ need to be experienced first hand. |
Just as a note, it's a common recording engineer technique to use a high pass filter when tracking or mixing.
To Johnnyb53:
If you limit the audiophile world to only stand mounted speakers, then I would agree that there is not robust performance below 50Hz. But that's not what you originally said, nor is it an accurate description of what many audiophiles have. When I look at other members virtual system I see a majority of full range, floorstanding loudspeakers.
Everything you say about adding a subwoofer is true, but the benefit you describe is audiophile, not musically relevant. |
Hmmm.. I looked into undertone a bit as well as phantom tone etc.
http://en.wikipedia.org/wiki/Undertone_series
It seems that undertone is rather rare unlike overtone which is all over the place. If the article is correct, only wind and string instrument can create undertone.
Piano can create tone lower than fundamental of notes struck through sympathetic vibration of lower strings.
Ecruz, I agree with you. I had similar experience with sub and perceiveds something similar so there is definitely something going on in the sub 40Hz area. |
06-21-12: Onhwy61
You can't count on many speakers to make meaningful bass below 50 Hz. Way too broad a generalization.
Really? I've been in audio for 43 years and worked in retail for awhile. I've listened to countless speakers and read countless speaker reviews that include response curves. In most ported stand-mounted speakers, there is a 5-10 dB hump around 80-100 Hz that drops off rapidly below that. If you reference the bass response to 1000 Hz, it's often down 10-15 dB at 50 Hz. Naturally, the bass response on floorstanders will be better, but for the small footprint towers, not really by that much. Mostly it buys better sensitivity. Only when you get into the larger and waaay more expensive floorstanders (and bigger stand-mounts like the stand-mounted TAD do you get serious bass below 50 Hz, and that select group IS NOT most speakers. Most speakers include all the junk that passes for hi-fi and the fact that mini-monitors far outnumber floorstanders. (JohnnyB53)
I'd say just about *any* loudspeaker would benefit from the right pair of subs properly blended.
(Onhwy61)
Benefit to a bass obsessed audiophile - yes. Required or needed for music reproduction - no. Bass obsession has nothing to do with it. If the subs are properly blended, they won't particularly excite the bass-obsessed. What they *will* do is provide a more linear extension through the musical frequencies to energize the listening area uniformly--more like a live concert--and reproduce very low frequency resonances of the original recording venue. In a symphonic concert hall this spectrum has a profound effect on the crackling excitement of in-room energy, even before the conductor raises his baton. This audible room energy separates listening to live orchestral music from what most people can listen to at home--unless they have sub(s) that go to 20 Hz or below. If you look around, you'll find reviews of powerful subs with sub-20Hz response that add soundstage and room acoustics to recordings of solo guitar--which by itself reaches only down to 80 Hz. |
I'm no expert but I gather that it is believed most likely the undertones or combination tones, when they exist, are created by our human hearing apparatus. IN that case the speakers do not have to produce the undertone frequency, our ears do that as a result of non linear inter-modulation distortion produced somehow by our ears and the rest of our aural nervous system.
But I gather this process is not really well understood. It could be that the undertones are real and in the recording, though I am not aware of how this could be accounted for scientifically. In that case, the speakers would have to be able to reproduce them in order to be heard.
Its one of those grey areas apparently that most likely is what it is and I personally would not worry about much.
Having said that, ideally, I like my speakers to go flat at lifelike listening volumes down to 20hz or so to the greatest extent possible without sacrificing elsewhere even if just as an insurance policy that I am not likely to miss anything good down there assuming it exists and I am able to hear it.
The reality is though that speakers that can do that and still do all the rest well do not come cheap and are probably the exception and not the rule. I am willing to punt somewhat on that full low end extension if needed in order to get the frequencies above that really matter right. Its a common scenario that applies to many I suspect. One of the many possible practical compromises an audiophile on a budget or with limited space must face. A good sub blended in properly can go a long way to help address the issue for many when needed. |
Not so sure either. If a recording captures, say, a 25hz tone that is a difference tone produced by two instruments' fundamentals (let's say 90hz and 125hz; just for argument, I am not up to the math right now) interacting acoustically, and the speaker playing back the recording has no output below, say, 30hz, then that 25hz tone is missing in the playback of the music. Now, does the presence in the recording of the two original fundamental tones mean that the acoustic interaction of these two tones in the listener's room produce the 25hz difference tone at the same level and with the same quality as what is heard live? I doubt it.
Moreover, why is it possible to hear the hall's sound in a live recording before a single note of music sounds from the recording; or in the rests in the music. Interesting tuff, no? |
FRogman,
I think we are in agreement save perhaps the technical details.
As I understand it currently from very limited reading on the topic, as long as the recording captures all the real harmonics produced by the instruments accurately, and the system including speakers deliver these up to snuff as well, the lower "difference" tone harmonics can be heard, but they are artifacts most likely produced by our listening senses, not explicitly by the speakers.
We might be saying the same thing, not sure. |
****so most likely not something that the speaker would play a role in producing assuming the speaker does in fact deliver the real instrument fundamental frequencies up to snuff.****
Some modern composers have exploited these difference tones in their music, and the tones are audible to the listener (audience). When I was in music conservatory we performed an experiment to find out if the remarkably loud difference tones produced by certain combinations of fundamentals heard in the performance of Eugene Bozza flute trios were captured by a recording, and they most certainly were. So I think while some of these effects may occur in the recesses of our hearing mechanisms only, undertones, in the usual sense, can most definitely be captured by the recording process, and hence need to be reproduced by speakers if the complete timbre of instruments is to be reproduced.
The cool thing about all this is that there is so much to this stuff that is still not fully understood. |
Or "combination tone"?
From what I read, it would seem to account for hearing frequencies lower than the fundamental but is believed to be most likely due to non linear inter-modulation distortion associated with how we hear more so than an aspect of actual sound per se, an "illusion" per se, so most likely not something that the speaker would play a role in producing assuming the speaker does in fact deliver the real instrument fundamental frequencies up to snuff. |
****Clearly a sub often if not usually makes a big difference but the existence of lower frequencies in the harmonics is not required to explain it.**** - Mapman
Very true, but it is required when the sub is used in a purely "augment" mode as many (most) subs are used; as opposed to using the sub's internal xover, when the benefits you describe are technically as well a audibly obvious.
Another term for undertone is "difference tone". |
|
Clearly a sub often if not usually makes a big difference but the existence of lower frequencies in the harmonics is not required to explain it.
Often when adding a sub, the difference can be the result of the sub being able to better deliver flat response without compression at louder volumes at even the same frequencies that the mains would have to cover otherwise, along the lines that Drew_Exckhardt explains so nicely in detail in his posts.
The chart indicates "low fundamentals" for several instruments. Not sure what that is or how different from the "fundamental". Could it be the same thing as frogman's "undertones"?
There is [url=http://en.wikipedia.org/wiki/Missing_fundamental]This[/url] that I found which seems relevant to the discussion. |
Ecruz, I wrote my post just after and before reading yours. Your account is a perfect example of what I described. |
There exists an acoustical phenomenon called "undertones". Two frequencies sounding together create a phantom tone well below the fundamental frequency of either of the original tones. Just as with "overtones" (harmonics), the presence of these undertones is a large part of what gives instruments timbral complexity, and what allows one to hear or sense the volume of the space that the instrument or voice is playing in. The sound instruments playing together or alone is a practically infinite matrix of the interactions of fundamental tones and harmonics (under and overtones). If a system cannot reproduce the lowest frequencies, the sound of instruments will definitely be impacted. How much and how important that particular aspect of sound is, is a personal call when we consider how many other things there are that affect correct record/playback. |
FWIW, I'll share my experience on this.
I once heard a demo at a local shop. It was a recording of an acoustic guitar. Nothing else. Don't remember exactly what speakers I was listening to. I listened for a while, it sounded very nice. The dealer then said," I'm going to switch things up a bit and let you listen to the same recording, same speakers, same amp. Tell me what you think". I listened again, wow! It sounded more real, deeper soundstage, more immediate, etc. Like the notes were floating out there instead of coming from the speakers. I asked if he switched cd players? "Nope", he said, "I turned on the REL sub in the corner over there".
Even if the notes only go down to 40hz, there's something below that frequency that we feel or sense or something. |
You can't count on many speakers to make meaningful bass below 50 Hz. Way too broad a generalization. I'd say just about *any* loudspeaker would benefit from the right pair of subs properly blended. Benefit to a bass obsessed audiophile - yes. Required or needed for music reproduction - no. |
"I'd say just about *any* loudspeaker would benefit from the right pair of subs properly blended."
That's true because it is adding more power (assuming powered subwoofers) to the whole system and low frequency reproduction takes lots of power. Properly blended is the key and that doesn't come cheap. Plus, at some point the stereo will either run everyone out of the house or shake the house down. The ultimate plight of the over-enthusiastic audiophile. |
06-20-12: Paulsax
I seem to recall that a typical electric bass guitar drops to mid to high 30's on the open low string. For some reason 38 is sticking out in my mind. lots of fronts will do that but the discussion on spl above my explain why the sub helps out.
If you check this chart, you will see that the low E of a 4-string bass is 41.203 Hz. For a 5-string, the low B is 30.868 Hz. Maybe that's what stuck in your mind (with a little modification). Or maybe you were thinking of Eb, which is 38.891 Hz. Your second part is definitely true. You can't count on many speakers to make meaningful bass below 50 Hz. Many start rolling off around 80-100 Hz. Of course this depends on speaker placement, room-loading, etc. And more expensive speakers definitely go lower. Still, if Wilson Audio tours the Alexandria XLFs with a pair of Thor subs, I'd say just about *any* loudspeaker would benefit from the right pair of subs properly blended. |
I seem to recall that a typical electric bass guitar drops to mid to high 30's on the open low string. For some reason 38 is sticking out in my mind. lots of fronts will do that but the discussion on spl above my explain why the sub helps out. |
Just to be clear, the SB touch frequency spectrum display would indicate the frequency distribution of the signal the touch receives as input. I wonder if it is based on the digital input signal or the analog output of the internal DAC? Dunno.
ANyway, my point is that this is different than the response one would measure with a microphone if one were to do that with another similar device that works with a microphone as input. Furthermore, what the mike would measure would depending on placement location in the room due to room acoustics. The normalized differences between the two at any point if analyzed somehow would tell you the effects of the room acoustics compared to the source music signal.
Probably some good fodder in there for another thread or two on how to quantitatively measure source material quality and/or related system performance. I am not up to date on all the specific devices/programs that can do this but the technology surely exists and could be applied by inquiring minds fairly easily these days I would expect. |
Drew: I understood that speaker frequency response is measured in an anechoic chamber so that consistent comparisons can be made with regard to speaker response performance. In the real world, the speaker sits on a hard or soft floor, close to or far from walls and ceilings. These variables, plus furniture, curtains and rugs create colorations in the music and then we must consider the type of amplifier and cables attached to the speakers and how they respond to the impedence characteristics. So speaker designers can create an instrument that looks perfect on paper when operated in an ideal environment, but how it behaves in our homes can be an entirely different matter, right? For example, just placing speakers near corners in a room can reinforce the base or adding curtains on the wall can dampen down the highs. I also learned in the past that too much dampening in the room kills the music. I have my speakers positioned a good distance from any wall. My speakers sit on spikes on a wood floor but I have a good sized rug placed directly in front of them. I haven't made a detail spectrum measurement but I believe I am close to a flat response curve as I could possibly get. Not saying that it is flat, just that I have acheived a satisfactory balance. I think about all of the parameters that speaker designers must consider both acoustically and electronically and then the nearly infinite variables of peoples' listening enviroment, associated cables and electronic gear and I can see why we have so many types and styles of speakers. |
Other points about low frequency extension are that
1) It's not a brick-wall. Extension to 50Hz generally means that output is at least 3dB down at that point with a noticeable 1dB of drop up much higher like at 80Hz.
2) The effects are worse than the numbers would suggest due to the equal loudness curve spacing at low frequencies. Once you get to 50Hz at moderate listening levels 3dB is like 6dB down at 1KHz which is 1/4 the acoustic power and quite significant (a full 10dB gets you a perceptual halving of volume).
3) The -3dB extension does not imply that the speaker is actually flat to that point. Many small speakers have a bump in frequency response (a few dB) which boosts the harmonics of low frequency instruments and can either give the impression the missing frequencies are still there or make the speaker sound boomy depending on what they're trying to reproduce. This design choice is more likely in speakers with less low frequency extension. |
FWIW, Squeezebox touch has a frequency spectrum display mode that can be switched to by touching the display area where album art is displayed by default I believe. Dunno how accurate, but it appears to be somewhat useful to get an idea of what the frequency content of what is playing is. A nice bonus feature! Also has a VU meter display for those that miss those on our modern gear. Very pretty! |
I tend to think similar to Drew_eckhardt.
A speaker that is flat and can perform without breakup nor compression at real life volumes best will tend to extend similarly below the frequency range where the lowest and most common fundamentals occur even if not much really occurs down there. Not only does this best cover pretty muchanything we might hear that is there but it also is an insurance policy that the speaker has the bandwidth to deliver as needed where it is most likely to matter.
For lower volume listening, at levels safer to the human ear, this will all tend to matter much less or not at all. |
I have spectral analysis software on my laptop (the OmniMic from Parts Express), and a surprising number of recording show sub-30Hz energy, especially Telarc CDs. If you're into contemporary jazz I think the 20-40Hz octave is critical for really hearing what's on the recording.
Over the past year I've become a huge fan of subwoofers, and not because I want to blow myself out of the room with bass, but because you can sometimes get much smoother bass by placing one or more subs in appropriate locations than you can with just a pair of stereo speakers. It is really the smoothness of the in-room response between 20Hz and 100Hz that determines bass quality.
If you get an OmniMic or a similar set-up and measure your in-room response you might be very surprised at the number peaks and dips you see, often exceeding +/- 10db. Every room has different modes, and moving your speakers even an inch one way or the other can often make a big difference. |
06-18-12: Suteetat
Johnnyb, thanks for your information. That's exactly the kind of info I am looking for. Any idea how low those bigger kick drum can go down to? I also have not been able to find much information about the big bass drum that are used in some classical music such as Verdi's Requiem, Stravinsky's Firebird as far as their frequency is concerned.
Yeah, I noticed that the concert bass drum isn't included on that musical frequency chart. I've heard the large concert bass played many times and have played them several times in orchestras. The big ones have to be making an honest 30 Hz and maybe lower. The difference between the big bass drum and the low A0 on a piano is that even on a 9' grand, most of what you hear live on the lowest key is overtones, but with the concert bass drum you're hearing primarily a very strong 30 Hz (or thereabouts) fundamental with a very strong initial transient. The effect is dramatic. I'll be hearing one plenty this Thursday as I'm going to the Seattle Symphony performance of Berlioz's "Damnation of Faust." |
I have had speakers with a flat frequency response down to 20Hz and my current speakers are flat to 27 or 28Hz. I haven't missed those bottom 7Hz. I occasionally heard thumps in recordings like in the first Cowboy Junkies Album with my old speakers that I don't hear now, but that wasn't really music or part of the music. It was like someone's foot banged into the mic. More just ambiance that was not really adding to the music. I think speakers have a full sound or a nice robust fullness if they can get down to the low 30s. Monitors that start to fall off in the 40s sound good and musical to me, just a little light in the bass and missing that kick or punch in the bass. Maybe it depends on the amplifier and cables too. I can play Fresh Aire III on vinyl and the drums go right through the floor with my current speakers/amp- much deeper feeling as I remember vs. my old speakers/amp combo that went down to 20Hz. |
Oops! I just clicked on the poster's link and found it is the same chart. |
There is an audio frequency chart linked in another thread under speakers. It shows the frequency range of musical instruments. It is under the thread titled, " Thoughts from THE Show, is $29k the new $10k?". |
Johnnyb, thanks for your information. That's exactly the kind of info I am looking for. Any idea how low those bigger kick drum can go down to? I also have not been able to find much information about the big bass drum that are used in some classical music such as Verdi's Requiem, Stravinsky's Firebird as far as their frequency is concerned. |
For me, having a flat response down to at least 30hz is also for hearing the space the music was recorded in. I like listening to a lot of live recorded jazz tracks and such and find the low bass replays the resonance of the particular room of the performance. i.e, one live jazz album I have sounds as if it was played in a venue in a high rise building on a windy day. There is just that low frequency resonance that you get in such a building. Or I was once listening to a track of a choir in an old large church and there must of been a truck passing the road outside the church. It had that unique sound of outside traffic noise passing through the thick stone walls of an old church.
Maybe some people think such sounds will subtract from the music... but to me it adds to the sense of 'being there'. And individual tracks have their unique character that regard. |
06-18-12: Suteetat
Drew, thanks for your information. I certainly don't disagree that giving bass extension can help to improve midbass performance as well. However, I don't think that it would answer my question regarding playing music that contains fundamentals that are only 50Hz or above as to what kind of sound, information or contents those recording contains that are below 50Hz?
You make a good point that if speakers are strong, linear, and honest down to 40 Hz (not 50--it's just not low enough), you are going to hear most of the music and the system will come across as having excellent bass. However, a great number of speakers actually start rolling off around 100 Hz and have pooped out around 50-60 Hz and they are definitely missing something. Even augmenting such a system with a sub that itself rolls off at 36 Hz will make a positive and noticeable difference. Furthermore, not all kick drums' fundamental tone is around 50 Hz; it depends on the drum size and the tuning. My vintage Slingerland 14"x22" has a lower thump than that, and many kick drums today are much larger, like 20"x24". Even the fundamental on a snare drum can provide a workout for a good woofer. Another thing: the low E of a 4-string electric bass is around 42Hz, but many rock/pop bass players use a 5-string, whose lowest note is about 32 Hz. It's just one whole note above the bottom A of a standard piano. If you have a system that's truly flat to 40 Hz it'll sound strong on rock and pop, but if it's flat to 30 Hz you'll hear the difference on many recordings, especially later ones. |
Drew, thanks for your information. I certainly don't disagree that giving bass extension can help to improve midbass performance as well. However, I don't think that it would answer my question regarding playing music that contains fundamentals that are only 50Hz or above as to what kind of sound, information or contents those recording contains that are below 50Hz? I am not trying to pick on recording studio, sound engineer regarding equalization or anything like that but actually try to understand more about what I hear. |
