First, if you like swarm, that’s fine, please start a thread somewhere else about how much you like swarm.
I want to talk about the impression that subs are fast or slow compared to planar or line sources.
The concern, and it’s correct, is that adding a subwoofer to say a Martin Logan or Magneplanar speaker will ruin the sound balance. That concern is absolutely a valid one and can happen with almost any speaker, not just speakers with tight dispersion control.
What usually happens is that the room, sub and main speakers aren’t integrating very well. Unfortunately for most audiophiles, it’s very hard to figure out exactly what is wrong without measurements or EQ capabilities in the subwoofer to help you.
So, there’s the myth of a small sub being "faster." It isn’t. It’s slower has worst distortion and lower output than a larger sub but what it does is it doesn’t go down deep enough to wake the dragons.
The biggest problems I’ve heard/seen have been excessively large peaks in the subwoofer range. Sometimes those peaks put out 20x more power into a room than the rest of the subwoofer. Think about that!! Your 1000 W sub is putting out 20,000 watts worth of power in some very narrow bands. Of course that will sound bad and muddied. The combination of sub and main speaker can also excessively accentuate the area where they meet, not to mention nulls.
A lot is made about nulls in the bass but honestly IMHO, those are the least of our worries. Of course too many of them can make the bass drop out, but in practicality is is the irregular bass response and the massive peaks that most prevent any good sub from functioning well in a room.
Bass traps are of course very useful tools to help tame peaks and nulls. They can enable EQ in ways you can’t do without it. If your main speakers are ported, plug them. Us the AM Acoustics room mode simulator to help you place your speakers and listening location.
Lastly, using a subwoofer to only fill in 20 Hz range is nonsense. Go big or go home. Use a sub at least at 60 Hz or higher. Use a single cap to create a high pass filter. Use EQ on the subwoofer at least. Get bass traps. Measure, for heaven’s sake measure and stop imagining you know a thing about your speaker or subwoofer’s response in the room because you don’t. Once that speaker arrives in the room it’s a completely different animal than it was in the showroom or in the spec sheet.
Lastly, if your room is excessively reflective, you don’t need a sub, you need more absorption. By lowering the mid-hi energy levels in a room the bass will appear like an old Spanish galleon at low tide.
"The biggest problems I’ve heard/seen have been excessively large peaks in the subwoofer range. Sometimes those peaks put out 20x more power into a room than the rest of the subwoofer. Think about that!! Your 1000 W sub is putting out 20,000 watts worth of power in some very narrow bands. Of course that will sound bad and muddied."
Well written; you really put it into perspective!
No SUBWOOFER is that bad all by itself. However the subwoofer+room INTERACTION can be that bad, even with a superb subwoofer. And said interaction doesn’t have to be THAT bad to still be really bad.
In the bass region, imo the INTERACTION of subwoofer + room IS the "elephant in the room"; the uncomfortable-to-acknowledge, difficult-to-deal-with thing.
I agree with you that the bass-region dips are perceptually benign relative to the peaks.
And those peaks are perceptually even worse than they look on paper: Note that the Equal Loudness Curves bunch up south of 100 Hz. So what happens is, a 5 dB peak at 40 Hz can be perceptually comparable to a 10 dB peak at 1 kHz!
The ear’s heightened sensitivity to changes in SPL in the bass region is one of the reasons why it can take a long time to dial in the correct level on a subwoofer (those maddeningly-small knobs are another). On the other hand, the reduction of those peaks makes a PERCEIVED qualitative improvement greater than one would expect just from eyeballing the before-and-after curves.
I agree with pretty much everything you went into detail about.
@bjesien: Because it sounds so much better. In almost all cases when users have a high pass filter they are astonished at how much better their main speakers sound passed high vs. passed low.
The naive (without actual experience) is that you paid megabucks for your main speakers, so they should be much better than your sub which costs 1/5th or less.
The reality is, almost always, that your main speakers perform so much better when relieved of more bass.
My apologies I didn't read the whole post. I had a pair of Vandersteen 5's that had a high pass filter to just run the top portion in essence doing what you are saying here.
Haven't tried to high pass any other speakers but I do know some of mine over the years sounded worse with a sub, some better. If they really do go down to 30hz (rare) I found I didn't want one. 34-higher, yes for sure.
I beleive you. The issue with subs, always, is integration. It is hard without measuremengs and nearly impossible with them. I applaud Vandersteen's use of high pass filters, but recognize how hard the rest of it can be before you get good results.
The biggest problems I’ve heard/seen have been excessively large peaks in the subwoofer range. Sometimes those peaks put out 20x more power into a room than the rest of the subwoofer. Think about that!! Your 1000 W sub is putting out 20,000 watts worth of power in some very narrow bands. Of course that will sound bad and muddied. The combination of sub and main speaker can also excessively accentuate the area where they meet, not to mention nulls.
A lot is made about nulls in the bass but honestly IMHO, those are the least of our worries. Of course too many of them can make the bass drop out, but in practicality is is the irregular bass response and the massive peaks that most prevent any good sub from functioning well in a room.
Either scenario (i.e.: peaks and nulls) in the extreme is one not to be desired. It’s their combination in particular that can tip the boat, but remember that corrected nulls require power; peaks don’t. So, peaks have one sitting with a surplus of acoustic power that can be counteracted with a narrow range of power suppression, whereas nulls have one in the need of actual, added electrical ditto. Thus, practically speaking power requirement can be the more predominant issue at hand.
If a distributed bass array is not an option we are dealing with frequency irregularities in the bass in the first place, even with pairs of subs, and the damn thing about absorption is that to alleviate peaks sufficiently, on its own, it can have a damaging effect on the overall presentation in other areas. I always go about sparingly with absorption, and would rather have the rest of the corrective measures done with digital room correction and/or a more manual approach with frequency correction via a DSP - preferably actively. On the other hand excessive use of DRC has its own disadvantages, or so I find, and so in the end there may be an element of one needing to accept an extent of FR-irregularities with a limited amount of bass sources. Or, a DBA is called for, and one placed symmetrically to the mains rather than a mono-ed asymmetrical ditto.
Lastly, using a subwoofer to only fill in 20 Hz range is nonsense. Go big or go home. Use a sub at least at 60 Hz or higher. Use a single cap to create a high pass filter. Use EQ on the subwoofer at least. Get bass traps. Measure, for heaven’s sake measure and stop imagining you know a thing about your speaker or subwoofer’s response in the room because you don’t. Once that speaker arrives in the room it’s a completely different animal than it was in the showroom or in the spec sheet.
Definitely agree on the high-passing of the mains higher than lower - not only does it more effectively relieve the mains from LF but it also has you go about the overall integration with the subs much more effectively when controlling the HP of the mains over a range as well, which is akin to approaching it more as a single speaker system per channel than simply adding on the subs to the mains run full-range. There’s this misconception generalizing that high-passing the mains higher (say, >60-70Hz) is more suited to Home Theatre than "audiophile" use, which goes contrary to my own experience. To my ears high-passing higher (with a fittingly higher subs low pass as well) is usually more suitable on the whole.
With regard to "slow bass" I believe there’s some merit to considerations on overhang and/or group delay inherent to a design that will impact the presentation regardless of the integration with the room/FR-smoothness.
@phusisNo one wants peaks or nulls, but IMHO and experience, peaks are worse. Of course, mathematically we can compute power differences for each, but peaks are bad because they tend to force the listener to keep the overall subwoofer level excessively low. OTOH, I’ve never seen a real system where the nulls were so pronounced that they forced an excess in sub volume. Maybe I got lucky.
In my experience, clipping the peaks and then raising the subwoofer level is 2/3rds of the battle.
The purpose of this thread was to discuss the myth of subwoofer speed, not any particular technology, and it invariably happens that SWARM fanboys show up and turn the thread into "WHY DON"T YOU HAVE SWARM" and take the discussion far afield from it’s intended point.
So, sure, any tech which evens out the peaks and nulls and correctly meshes the response of the subs to the mains is good, including SWARM, but this thread is about dispelling myths that you can’t add a sub to a "fast" speaker, not pushing any particular solution.
The sense of a subwoofer being bloated, or peaky or slow can be addressed with a single subwoofer or swarm. The problem is the finesse involved which first time subwoofer owners may be completely unprepared for.
Installing 1 subwoofer correctly is a big deal and a lot more work than most audiophiles want to do. Tripling the number of speakers (from 2 to 6) for SWARM is also a big deal for many. Failing to do either well is what makes for slow, mushy or overbearing sub experience.
Either of these approaches can dispell the myth that big cone subs are slow and unable to keep up with "fast" planar speakers. OTOH, lets be realistic that audiophiles are also unprepared for the work they’ll have to do in many cases to be done.
I guess my point is, I wanted to focus on all the problems which makes audiophiles call subs slow to point out how much has to be right.
In the service of that, I have no problem with users having very positive experiences with one approach or another (including SWARM) but would like to see more discussions about SWARM taken to their own threads. "How I solved all my bass problems with SWARM" would be a good title for a thread someone else starts I think.
I think audiophiles are 100% correct when they say adding a sub to a great sounding pair of speakers ruined the sound, but usually WRONG about why it went bad. That's what this thread is about.
What size cap. would be needed to high pass to the main speakers at about 60-80 HZ? (assuming an 8 Ohm speaker)? I would think it would be pretty large, or parallel a few.
And yet again, you seem to have no idea about what’s meant by fast or slow bass. I recall that i’ve tried to explain this to you before, but, it appears that it hasn’t clicked.
Here’s the video you need to watch. LISTEN, LEARN AND STOP SPREADING MISINFORMATION ON THE FORUM.
@deep_333- Sorry, got distracted by an ad that told me I could cure diabetes with baking soda, so this is how I know that everything on Youtube is real.
PS - IMHO, bass should not be "fast." It should be glorious. That is, it shouldn’t sound like you are listening to a bullet traversing the air, nor should it feel like a hammer in your chest.
Excellent bass should be clear like air or water and evidence itself only by the scale and dynamic range of the music being played and seemingly come out of nowhere and ignores the physical size of the room.
@deep_333 - Sorry, got distracted by an ad that told me I could cure diabetes with baking soda, so this is how I know that everything on Youtube is real.
Ah, no surprise, the ego has taken over again. When you have the humility to admit that you didn’t know something in life, the possibility of learning something occurs. Until then...keep at it. Any engineer worth half his salt will admit that engineering is a life long process of learning (the humility to admit that one doesn't know sht at specific levels and constantly keeping the possibility of learning open). But, when it comes to all the self proclaimed forum experts, accountants and their giant egos, they already know everything there is to know...and "what they do not know may not ever exist!"...whoop di doo.
Anyone that has used a sub without a highpass is doing it wrong. My current speakers have 15” bass drivers and I still highpass at 65hz. If I had better subs I would probably highpass even higher.
The Danny Richie video is interesting. I often find his videos very well done and have a lot of great info. His explanation of speed is interesting, though. First, he comes out and states that the driver output tracking the signal input is not "speed of the woofer". He then spends ten minutes contradicting himself and explaining all of the things he has done to prevent driver ringing or droning, which put in simple words is that the driver output matches the input. The driver starts and stops moving exactly as the signal dictates. That is the reason that servo control exists, so that the driver output matches the signal input.
Any ringing is bad, whether it be in the box or in the room. It doesn't matter if what is coming out of the driver / box is perfect if the room is mucking it up. There are many errors in setting a sub up that can make matters worse. As hard as it may be for at least one person here to believe, both Danny and Erik can be correct at the same time and have valid points.
Anyone that has used a sub without a highpass is doing it wrong
I don’t think it’s IMPOSSIBLE.... but very difficult to do this by ear or based on published specs or measurements. You must figure out what your main speaker is doing in room. I repeat, in room speakers are entirely different creatures. It’s like you go to the store, get a sweet puppy which tries to eat your eyeballs as soon as you get it home.
IF you have a DSP based system, and only do the subwoofer, you often end up wiht very complicated EQ at the transition area, so, practically speaking, yeah it's nigh impossible.
Excellent bass should be clear like air or water and evidence itself only by the scale and dynamic range of the music being played and seemingly come out of nowhere and ignores the physical size of the room.
I agree and the way I achieved this is using an active crossover with 70 Hz low pass and high pass filters (4th order 24 dB Linkwitz-Riley) and biamping with a SWARM set up using 4 woofers.
No one wants peaks or nulls, but IMHO and experience, peaks are worse. Of course, mathematically we can compute power differences for each, but peaks are bad because they tend to force the listener to keep the overall subwoofer level excessively low. OTOH, I’ve never seen a real system where the nulls were so pronounced that they forced an excess in sub volume. Maybe I got lucky.
In my experience, clipping the peaks and then raising the subwoofer level is 2/3rds of the battle.
The highlighted parts are important points I’ve tried to raise at numerous, previous occasions - certainly the aspect that many end up lowering sub(s) gain to suppress not only peak issues in the range here, and thus are deprived of sufficient low end presence and overall quality.
To clarify on the corrective measure of peaks/nulls: it is my experience that nulls, which can be quite severe, require sometimes a fairly prodigious amount of extra power to be alleviated, and this can put a strain on the amp(s). At the same time peaks do the opposite to some degree, which may end up at least partly nullifying the added power demands from peaks, but from my chair this is usually not enough to keep nulls from being a potential power issue correction-wise, to the point even where the driver is also stressed.
The purpose of this thread was to discuss the myth of subwoofer speed, not any particular technology, and it invariably happens that SWARM fanboys show up and turn the thread into "WHY DON"T YOU HAVE SWARM" and take the discussion far afield from it’s intended point.
So, sure, any tech which evens out the peaks and nulls and correctly meshes the response of the subs to the mains is good, including SWARM, but this thread is about dispelling myths that you can’t add a sub to a "fast" speaker, not pushing any particular solution.
First, if dispelling named myth is the goal then be prepared for a variety of suggestions on how proper subs integration can be achieved. I don’t yet SWARM myself (though down the road I’m contemplating a symmetrically set up DBA with smaller tapped horn, similarly tuned variants), and my intention was not to be the "SWARM missionary" here but rather to lay out the challenge with a more limited number of bass sources (say, no more than 2 bass sources). Yes, SWARM presents challenges as well, but personally I find 2 subs a mandatory outset for serious sub integration, and one that lends itself naturally with a main speaker high-pass above the 60-70Hz range (i.e.: where directionality sets in when not using absolute brick wall low-pass slopes) placed symmetrically to and (fairly) close to the main speakers with the subs configured in stereo.
Installing 1 subwoofer correctly is a big deal and a lot more work than most audiophiles want to do. Tripling the number of speakers (from 2 to 6) for SWARM is also a big deal for many. Failing to do either well is what makes for slow, mushy or overbearing sub experience.
Either of these approaches can dispell the myth that big cone subs are slow and unable to keep up with "fast" planar speakers. OTOH, lets be realistic that audiophiles are also unprepared for the work they’ll have to do in many cases to be done.
Indeed they often are.
IMHO, bass should not be "fast." It should be glorious. That is, it shouldn’t sound like you are listening to a bullet traversing the air, nor should it feel like a hammer in your chest.
Excellent bass should be clear like air or water and evidence itself only by the scale and dynamic range of the music being played and seemingly come out of nowhere and ignores the physical size of the room.
When you put it that way (and it’s a very good description of what great bass can sound/feel like) I’ll have to say very few ever get to experience bass like that. Such bass presentation only comes from prodigious effective air radiation area, loads of headroom (i.e.: very low distortion and thus ease) and excellent overall integration.
However, with reference to your second paragraph just above I’d go further and say there is a particular design approach that aids the traits mentioned by you (even though you don’t want to get "specific"), and that’s horn-loading or a variation thereof; that particular "coming out of nowhere," omnipresent and liquid/smooth sense of the lower octaves that swell effortlessly with dynamic swings and don’t call unnecessary attention to itself is a definite quality of large, horn-loaded subs. Direct radiation with larger, or multiple smaller cones (remember, horns are force multipliers that make smaller cones deliver similar or even more total air pressurization) just make themselves and their cones known more predominantly - even to the point of becoming a distraction when you know the difference horns can make. It comes down to cones in horns moving very little to produce even staggering output, as well as the gradual impedance match of cone-to-air coupling of horns, with all that entails, likely in combination with the woofer cones being partly or entirely hidden in the horn path and thus prevents mechanical distortion and upper end harmonics to more readily enter audibility (effectively acting also as a low-pass filter). It’s more of an immersive, musical flow of low frequencies than the more ground-based and differently tactile sense of bass from direct radiators, to my ears.
@erik_squireswrote: "Installing 1 subwoofer correctly is a big deal and a lot more work than most audiophiles want to do. Tripling the number of speakers (from 2 to 6) for SWARM is also a big deal for many. Failing to do either well is what makes for slow, mushy or overbearing sub experience."
If you are using a single subwoofer, the location of that single subwoofer may well be, and often is, critical.
But the more subwoofers you use, the less critical the location of any one of them becomes.
@audiokinesisis not wrong, but the SWARM solution, like adding EQ, and traps, is probably NOT what audiophiles expect when they first think of adding a sub.
SWARM and other approaches prove however that the issue is not the size of the sub but the room /sub/speaker integration. 15" subs don’t sound bad because they are 15". They sound bad because most have no idea how much they’ll need to make them sound good.
The idea that large drivers have excess stored energy which they can’t get rid of fast enough is bunk. That, and that alone, is my point. Which set of challenges audiophiles decide are best for them is for another thread.
@phusisI don't think we can entirely stop talking aobut potential solutions, whether that be my preferences, SWARM or a horn loaded woofer, because ultimately they all prove the idea that large drivers aren't fast is simply not the real problem.
@audiokinesisis not wrong, but the SWARM solution, like adding EQ, and traps, is probably NOT what audiophiles expect when they first think of adding a sub.
Again I agree, but audiophiles are less about education and more about aimless tweaking. So when they add a sub they expect it to be plug and play and not something they have to educate themselves on.
The idea that large drivers have excess stored energy which they can’t get rid of fast enough is bunk. That, and that alone, is my point. Which set of challenges audiophiles decide are best for them is for another thread.
I think the Danny Ritchie video linked earlier by @deep_333proves this point, although I have had good success with 8" and 10" drivers and have no desire to go larger than that.
@james633 Anyone that has used a sub without a highpass is doing it wrong.
After crawl test positioning and playing the Sweep Tone CD the Velodyne Plus software measures the speakers from 200Hz and the subs from 100Hz - 15Hz in room simultaneously.
The software automatically feathers in the subs fourteen Optimization Parameters within the eight frequency bands beginning at 100Hz self designing a crossover region that uncannily maintains the speakers low frequency presentation quite closely as they roll off, in roughly twenty minutes.
The speakers remain in the analog chain at full range during the process.
While high pass filtering is a Plus option, with an abundance of speaker amplifier power the filtering is noticeably less desirable.
I have had good success with 8" and 10" drivers and have no desire to go larger than that.
In many rooms that may very well be ideal. While I could argue you'd get more out of a larger sub, there are dragons in the depths and not messing with success is a good principle to live by.
While high pass filtering is a Plus option, with an abundance of speaker amplifier power the filtering is noticeably less desirable.
Honestly disagree. There are measurements showing that less bass = less IM distortion from main speakers, and many attribute this reduced IM/doppler distortion to some of the benefits possible. I’m not sure how much of that matters, but I can say, conclusively, that the high pass filters absolutely make the main speakers sound better.
Also, as an aside, Monitor Audio recently produced a high tech speaker, not sure if it was a prototype, with woofers facing each other, so you listen at 90 degrees to their motion, and I’m convinced this is an attempt at solving that particular problem.
From a power/efficiency point of view, you are right, no reason to high pass or use active crossovers in a home environment, but if you ask me if it sounds better, I am completely convinced it does.
First is to identify what is fast bass? Where does this sound live? If you're looking for for bomb explosions and car crashes then 20hz is great but there isn't much of this in music. The deeper 'punch' for music lives in the 30 to 50 range. I want the woofers of my main speakers to participate. Experiments of plugging ports on main speakers has resulted in reduced excursion (restricts speaker movement) and lowered the volume output of the speaker and a LOSS of richness in mid bass. Not good. Let them remain open as they were designed to be.
As the main speaker begins to drop off around 40 to 50hz this is the area for the 'SUB' woofer to help. Again, the main speakers will handle the upper bass no problem. My experience is that the subwoofer quickly becomes excessively 'boomy' at higher crossover settings above 60hz. (this depends on your main speaker capability)
What works for me...My main speakers are solid bass down to 50hz. I set an EQ with a 'sharp shelf filter' cut off starting at 35hz. I do NOT want the main speakers OR the subwoofer to try and reproduce lower frequencies that it doesn't need. I don't need 20hz for music. It only adds distortion. Let the sub be focused on the proper range for tight bass. 30hz IS deep bass in music!
The subwoofer 'low pass' is set to 40hz and will seam perfectly with the main speaker drop off at 50hz. Yes.. this is a tight range but I assure you it's the proper range for a 'SUB' woofer in music.
The key here is that, within this tight level, you can now increase the 'gain' level of the subwoofer fairly high. Both my subs have gain settings almost 3/4 of the way up so when it calls for power it's ready! Punch of a kick drum is immediate and powerful due to an unrestricted gain level.
You will never find tight punchy bass by setting a crossover high near 80hz or higher and then having to lower the volume to remove boominess. Like stepping on the brakes trying to go faster. That's completely backwards and is NOT what a subwoofer was designed to do.
@erik_squires I’m not sure how much of that matters, but I can say, conclusively, that the high pass filters absolutely make the main speakers sound better.
You're right. It does on some speakers. However, let's look at a 3 way speaker. The high pass filter will only affect the woofer. The tweeter and midrange are already 'high passed' through the internal crossover. So the woofer, that is perfectly capable of producing excellent mid/lower bass, gets restricted by a high pass.
Now you'll need to push the subwoofer to a higher crossover to compensate for the loss of bass. The subwoofer is not as good at producing upper bass as the high quality woofer you restricted using high pass.
Another way to accomplish this sound improvement is by using a lower shelf filter cutoff around 35hz. Eliminating the lower frequencies that you don't need will improve the sound of BOTH your main speakers AND your subwoofer. This way you'll retain the full sound of your main speakers. It's a win/win.
My ears much prefer the richer/fuller unrestricted mid bass sound without the high pass.
@gdaddy1 I’ve had my subs tuned to produce from 16Hz to 80 Hz. It was glorious with music. There was no reason to limit the output, BUT...
the frequency response was absolutely smooth without peaks and tilted downwards. About 1.25 to 1.5 dB/octave.
Overall, I know your approach is a popular one, but I disagree with it based on experience, and talking to audiophiles who have actually made the changes. The approach you are taking is have the sub do the least possible. I say, have it do the most, up to 80 Hz possible, and have the mains do the least. It's OK that we disagree, but I wanted to acknowledge your position so I could talk to it. Thank you.
Much of the benefit of a high pass before the mains amp is the loafing it enjoys…..
The problem w servo is input signal is compared w voice coil movement, NOT cone movements which are rarely pistonic….. But y’all like those big paper woofers flapping in and out of phase…..
Vandy powered bass: high pass the mains before amp, high level connectors to sub amp to provide identical transfer function, VERY linear pistonic drivers ( The sub 3 use 3x8”, the 7’s use a Titanium honeycomb core push pull dual voice coil driver ), 11 bands of ANALOG EQ below 120 hz to address room issues, and the 11 bands are NOT 1/3 octave for a reason…. An excellent “ learning engineer “,,,, would ponder on that seemingly unorthodox approach……
I want to highlight something I fear may be missed. I wrote this at the top of my original post:
I want to talk about the impression that subs are fast or slow compared to planar or line sources.
So this thread is about all the things that go wrong when adding a sub and how most audiophiles attribute this to the mass of the cone. That a 15" sub has too much inertia to be accurate, and is therefore slow. This thread is very much focused on what is perceived, which is poor bass, and how different that is from the actual root cause.
That is, I wanted to center listener perceptions instead of the physics, which are clear that big subwoofer drivers are the way to go, if only you didn't have a room you had to put them in.
There are some things that go wrong if you don’t high pass your mains too. Distortion and dynamic range are usually off, not to mention many times we EQ the sub but not the mains.
All drivers suffer from higher distortion at the lowest octaves they reproduce. Subwoofers do as well but at 2 octaves lower. So by leaving in the mains you are leaving that distortion in place. Next is dynamic range. Again, higher dynamic range, lower frequency and subs are absolutely going to win. You’ll end up with your mains producing significant distortion (harmonic and compression) levels you could have avoided by using a high pass filter.
I’m not sure that I know exactly which of these issues is why high passed main speakers sound so much better to me, but I suspect the answer is in one of these issues.
@tomic601Large, well made subs are efficient and have excellent pistonic motion in their intended frequency range and will deliver higher dynamic range.
Anyone who doubts this should just look at distortion specs for any 6-8" woofer and compare it to an excellent 15" driver. The distortion measurements don’t lie. Big is better and more accurate.
Play some well recorded Ray Brown or Starker SOLO and look at the RTA and know that EVEN with the super steep filters…that big paper driver….. expletive deleted….
@erik_squires The approach you are taking is have the sub do the least possible.
No. I want the sub to do the most it can do in the proper range to produce a fast, punchy sound (30 to 50hz). MORE gain not less. (BTW...16hz has no place in music.) Why would you do that? Just curious.
Good topic. It’s nice to "get the low down" on subwoofers from guys with a lot of experience with the subject.
Adding to the small vs large conversation:
Its been stated that speaker distortion is directly proportional to the movement (excursion) of the cone. Double the excursion, double the distortion. Cut it in half ... half the distortion. Taking the popular 10" and 15" driver sizes as an example, the 15" has to move less than half as much as the 10 to produce the same volume of air. Assuming that things are somewhat linear here (the "motor" in the 15" has sufficient power to do what it does well), the 15" will be cleaner at a given frequency and sound level. So, what about the added "mass" of the 15? We have to keep in mind that some of the "added mass" is the weight of the air itself. At the same frequency and same volume level, the "weight" of the air being displaced will be exactly the same. The differences will be the moving mass of the additional cone material, larger voice coil, etc. on the 15" which will be minimized by the cone moving less than half as much as the 10". Cone breakup is another form of distortion on larger cones that may also be offset by less cone travel being introduced. The quality of the execution by the manufacturer will be a key element here, but it is entirely possible that larger woofers will, in fact, have less overall distortion and produce "tighter" base than a smaller woofer.
We ordered in a 31" raw woofer many years ago because we were "hot rodders" who liked to mess with outrageous stuff. A 31" woofer has more cone area than 6 12" woofers, as a reference. I recalled mounting this thing in a 6 cubic foot sealed enclosure and running some test tones thru it. The rafters were, literally, shaking all over the building. A walk back to inspect the woofer revealed that the cone was moving about 1/4".
You will never find tight punchy bass by setting a crossover high near 80hz or higher and then having to lower the volume to remove boominess. Like stepping on the brakes trying to go faster. That's completely backwards and is NOT what a subwoofer was designed to do.
There are quite a few aspects to this. Depending on the nature of the bass response of both the main speakers and subs (from where they're positioned and further tweaked into place) there could be favorable scenarios for either solution, i.e.: a higher or lower subs-mains crossover point.
Making a general statement however that subs can't reproduce the range up to ~100Hz without sounding boomy is simply incorrect. Main speakers are usually positioned as a compromise taking both the range above and below the Schroeder frequency into consideration, whereas subs can be dialed in for low frequency reproduction exclusively with rather elaborate corrective measures via positioning, added bass sources, DSP and other.
Subs are also mostly actively configured, meaning direct amp-driver connection with dedicated amplification, much better woofer control to boot and a more efficient use of the power at one's disposal here without looking into a bunch of coils and what not of a passive filter.
There's also the problematic aspect of crossing over in the middle of the central bass area - that is, in the 40-60Hz range - and mixing what is likely two different bass signatures here. You could argue any crossover point is a potential issue, but to my ears - again, depending on several factors - the less intervening and most advantageous crossover point to subs typically sits somewhere between 80-120Hz handing over to the upper bass area. This way the mains are effectively relieved of LF (not least important when the woofer/mids of the mains cover the entire power region up to ~450-ish Hz, and possibly even higher), and the subs cover the most energy-rich area to which they can be favorably dialed in and are better suited to tackle. Subs sounding "boomy" are most likely badly implemented and/or badly designed/constructed or simply too small.
No…. the physics are super clear…. trade efficiency aka trashy output for pistonic motion…
Efficiency and low frequency reproduction means large size, and that again means the large cones/effective air radiation area generated move very little for a given SPL. Nothing "trashy" about that, but rather accommodated physics where they actually matter, but are less convenient for the interior decor-minded. Moreover, I can assure you "pistonic behavior" of well-designed typically pro segment woofers with anything but wobbly cones/suspensions here is the least of your worries in a domestic environment vs. a smaller and much less efficient driver (usually in the least efficient, sealed box with maximum cone movement at the tune) that needs excessive excursion by comparison for similar SPL. Potential mechanical noise issues galore, thermal compression creeping in, elevated distortion - you name it.
You will never find tight punchy bass by setting a crossover high near 80hz or higher and then having to lower the volume to remove boominess. Like stepping on the brakes trying to go faster. That’s completely backwards and is NOT what a subwoofer was designed to do.
Ahem, well, that was addressed really early on, but this is conflating a number of issues. I specifically mentioned that peaks had to be dealt with, often by EQ or EQ + bass traps. Remove them and you can raise the subwoofer level, no problem. That’s a completely different issue than the crossover frequency.
Same for using SWARM. I'd still recommend 80 Hz as an excellent starting point. Certainly better than 40 Hz.
@phusis most advantageous crossover point to subs typically sits somewhere between 80-120Hz handing over to the upper bass area.
Subs sounding "boomy" are most likely badly implemented and/or badly designed/constructed or simply too small.
After many, many tests...I respectfully disagree. So does REL.
From REL..."Almost 100% of the time, newcomers will set the crossover too high and the gain (volume level) too low. This will result in a sound that is fatter, boomier and improperly integrated with the main speakers. The secret is to realize the crossover needs to be lower than the main speaker’s output at which point the gain can be significantly higher resulting in very flat, natural and extended deep bass."
John Hunter of REL just has a different philosophy about how to use subwoofers. Not saying it's wrong, just different. As @tomic601alluded to earlier I come from a different school of thought, one taught to me by Roger Modjeski (designer of the electronic crossover for the Beveridge 2SW) who finally convinced me to use subs (8" woofer in a 1/3 cubic foot sealed box x 4) with my QUAD ESL speakers. His recommended LP and HP cutoff was 100 Hz. Why? Simple, the speaker was designed with a 90 Hz bump and that crossover point eliminates the bump. Now the QUAD ESL will never make anyone's best bass from a speaker list, but without that bump the speaker would have significantly less bass output, so there is that to consider as well. On my box speakers which are Spendor 1/2e I use 70 - 80 Hz.
Making a large diameter stiff structure is so easy…. i listen to two vastly different engineering solutions to the same problem…. 3 x 8” vs a push pull titanium honecomb bespoke Scanspeak driver…. like i said prove that big 15” paper cone stays in pistonic in the bandpass…. send it to germany….laser scanner does not lie…..
One should not confuse my argument as support for anything less than a systems engineering approach to the sub / room problem. The solutions i mention in a previous post include MUCH more than 3 x 8” drivers in a domestically attractive 90# box….. Obviously, i’m a Vandy owner and fan…. I’ve owned the big block gear, starting w Hartley … Infinity servo….Beveridge, etc ( i am…an old bastard… )carry on….and enjoy the music gents !,,,,,,
@clio09- Using a high crossover point to fix a low frequency bump is sound. I've done the same while making internal crossovers. It avoids extra EQ components.
My recommendation is usually to ask users to plug any ports for kind of the same reasons. It makes integration a little easier.
@tomic601Don't use a laser scanner to prove what you can easily see in distortion.
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