@mijostyn @lewm
So, it sounds like all three of us have SoundLab ESL's! That's quite unusual. Insofar as bass in SoundLabs is concerned, I would have to agree with @lewm . I've had the Atma-Sphere MA-2's hooked up to my speakers, and while the sound is quite pure, and the mid-range is perfect, they do have difficulty producing bass in the speakers. It seems that the SoundLabs perform very well without subwoofers with my amplifier. But, it appears we are veering off topic. . .
Unfortunately, we live in opposite poles of the country, as I'm in Florida, so I don't know that we'll be able to compare components easily.
@mijostyn
Does that track for resonance frequency on the Test LP inform you which frequency is being played; if not, how is it determined which frequency the stylus is vibrating to?
Thanks.
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@drbond , Yes of course. It announces every frequency as it goes down and has two tracks, one for vertical resonance and the other horizontal.
I do not have to worry about MA2’s making bass. I cross to subs digitally at 100 hz, 48 dB/oct. It is not about bass. It is about distortion and realistic volume levels. If you play a Bill Evans record, say Waltz for Debby at the volume the music had that night at the Village Vanguard, without subwoofers the SoundLabs will crap a brick regardless of what amp you are using to drive them.
I am down in Florida all the time. My sister lives just north of Miami and my step mother just south of Miami. You never come to New England? You need to come up the second week in October and see the colors. In Florida all you have is endless flatness, a few palm trees and hurricanes not to mention DisneyLand.
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"If you play a Bill Evans record, say Waltz for Debby at the volume the music had that night at the Village Vanguard, without subwoofers the SoundLabs will crap a brick regardless of what amp you are using to drive them."
With all respect, this is just wrong. Even though I am sick of "Waltz for Debby", though never sick of Bill Evans. And while I am sure there may be a rendition of WfD on one of the live VV performance albums (I’d have to check), he also recorded it in at least one studio session. Here’s where I debate whether to bring up the modification I made to the SL crossover that improved both efficiency and the impedance curve to suit our OTL amplifiers. The 845PX can reproduce the lowest frequencies of the bass player (Paul Motian?) on WfD at very satisfying SPLs. What it cannot do is blast you out of your seat on a hard rock recording, which I am sure Mijo’s subwoofers CAN do. And my Atma OTLs are more like MA1s than MA2s in terms of power output. (They are neither, use type 7241 triodes as output tubes on MA2 chassis’ using MA2 power transformers.)
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@mijostyn
I'm in central Florida, between Tampa and Orlando, probably about 3-4 hours from Miami. If you're interested in listening to the Dohmann, and the CH Precision P1, just PM me. If you can bring your (soon to be new) Channel D along to A-B, that would be fun!
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Dear @mijostyn : " without subwoofers the SoundLabs will crap a brick regardless of what amp you are using to drive them. "
You are rigth and is my experience not only with the Soundlab and other electrostatic . Electrostatic speakers could start to fail between 35hz-40hz and down listening at live MUSIC SPL and as you said it's a matters of distortion levels and that's why any passive dynamic speakers needs to works with subwoofers no matters what.
To handled " accurately " that low bass subwoofers is a must and have not substitute.
R.
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The thing is that Mijostyn chose a not very challenging piece of music (Waltz for Debby is hardly equivalent to the 1812 Overture), played by a jazz trio to boot. You say that any ESL starts to fall off at 35-40Hz. Even accepting that lower limit (which I don’t because the lower limit will be different for diaphragm surface area, stator to panel spacing, etc), there is probably nothing below 40hz (>2 octaves below middle C) in Waltz for Debby. There’s no way to prove my point, since you guys cannot make it to my listening room, but I have no problem with Bill Evans Trio playing anything at realistic SPLs. A small factor to consider also is that Mijo and I previously guesstimated that my speakers have about 400 sq in more radiating surface area compared to his (because mine are wider by 4 inches). Whether this makes a critical difference to bass extension or not, I do not know, but it doesn’t hurt. I also think the curvature of the PX speakers is greater than that of Mike’s speakers, and that might also reduce phase cancellation of bass frequencies. Finally, I do not and did not claim that using a subwoofer would not be beneficial where the music is a really severe test of bass delivery. And yes, a subwoof also helps in a more minor way to reduce distortion in upper frequencies. (Doppler distortion in panel speakers is real in theory and controversial in its actual importance.) Finally, my speakers are easier to drive than any OEM Sound Lab speaker all of which use an RC network in a passive crossover in conjunction with the bass and treble audio step up transformers. Having said all that, rest assured I do think about adding subwoofers once in a while, but if I did I would cross over at maybe 60 to 80Hz and use a very fast subwoofer that can blend with an ESL, not a behemoth. Meantime, since 80-90% if my listening is jazz, I do not feel deprived of bass.
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You got me to doing some research on the internet. This is on Wikipedia in the entry about the double bass, the instrument most commonly used in a jazz rhythm section: "The lowest note of a double bass is an E1 (on standard four-string basses) at approximately 41 Hz or a C1 (≈33 Hz), or sometimes B0 (≈31 Hz), when five strings are used. This is within about an octave above the lowest frequency that the average human ear can perceive as a distinctive pitch." The largest Sound Lab ESLs can easily reproduce the lowest tones in a jazz trio or small ensemble, given an amplifier that is suited to the job.
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Here's a reminder for the tone purists:
musical instruments (piano included) have complex harmonic structure: the fundamental has a frequency, but striking a note on a piano keyboard means as the sound resonates, many harmonics (integer multiples of the fundamental) also are generated. Each instrument has it’s own characteristic harmonic structure - what we can think of as timbre.
I think this can be summarized as "real music has distortions", albeit harmonic distortions, and, generally speaking, the louder the instrument is played, the more harmonic distortions are induced. This musical principle may not carry over to modern electronic music.
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@lewm , the wider speakers may have more baffling effect which theoretically might help them with bass extension. My point is that I do not want them making bass at all. At the volumes I listen at with the music I listen to (Porcupine Tree is on right now) The bass greatly distorts everything else and cuts my headroom by 10 dB or so. The Sound Labs I have are not standard models. They are 8 foot tall 645s. They have exactly the same horizontal dispersion as your 845's, 45 degrees. I did not go for the 845s as the additional width would have been a tight fit in my situation and the extra surface area did not matter to me as I already had a subwoofer array and the right equipment to manage it. I was getting plenty of volume out of the Acoustats, a speaker 16" narrower than the 645-8s. I was sure the 4"s would not be a sacrifice.
ESLs are not like dynamic speakers. They do not have the capability to take long excursions and they become non linear quickly under 100 Hz at higher listening levels. Because there is only one driver expected to cover the entire range the entire frequency range is affected by this non linearity. If you play them at lower levels avoiding the non linear zone of excursion they are fine. That is just not my style. Aside from this dipoles make very lumpy bass at best.
Subwoofers are a difficult topic. As @rauliruegas infers they are essential for realistic playback with almost any loudspeaker. Very few speakers produce adequate bass below 40 Hz. What a loudspeaker does at one meter is a far cry over what happens in a real room. The life and breath of music and the venue it was recorded in lies below 40 Hz. It is where concert halls breath and bass reverberates. It is the difference between a live performance and a transistor radio. To make realistic bass a system has to be tailored to it's environment. This requires digital signal processing. The only other way to do it is shear luck and you might as well buy lottery tickets.
Sorry for rambling on. I ripped my right forearm apart today, spent all day in an ER and am souped up on oxycodone.
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Oh please! You can preach even when you’re feeling good. There are pros and cons to the use of a subwoofer and I am aware of all of them. I wonder where you got the notion that ESLs per se as a class are nonlinear below 100Hz, and what do you mean by nonlinear? And what is the mechanism? No need to debate it here.
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@lewm . I'll put my black robe back on. While that is true about the double bass there is a lot more going on with a Jazz trio that will drop below 20 Hz, an undamped bass drum. The pulse you get when the bassist thumbs a string, the reverberation in the room.
Dipoles, because they are open baffle speakers create their own set of room interactions in the lowest octaves that depending on the room and the position of the speakers in it, can be severe. If your speakers are 5 feet away from the front wall you are going to have a problem at around 100 Hz. You can easily dampen frequencies above 250 Hz using acoustic tile behind the speakers, but there is no stopping frequencies below that. With a great room you can get reasonably flat bass throughout the room except at the walls using dynamic subwoofers. With enough power room control can take care of the rest.
By nonlinear I am referring to the tension on the diaphragm. Like any driver as the diaphragm travels over a certain point it starts to stiffen. This interferes with reproduction just like any other driver. Because of their large surface area ESL diaphragms do not have to move as far as a dynamic driver but still excursion is limited to a few mm and low bass notes at volume can easily exceed this. Sound Labs are actually worse because the diaphragm is segmented into small sections. On top of all this you have doppler distortion. Since our ESLs are "full range" drivers this affects the entire audio spectrum. With a two or three way speaker the distortion only applies to the spectrum of the woofer.
The real issue here is we listen to music differently. I hate being volume limited while you prefer lower volumes. I also will listen to raucous music you do not like. Yes, there are very dynamic moments in classical music, My favorite is in the last movement of Stravinsky's ballet, The Firebird. I be willing to bet I listen to that at a good 6 dB louder than you.
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No. We don’t necessarily listen differently, and I often listen at high SPLs. The crux of the matter is we listen to different genres of music. For example, I’ve never heard of the group you just mentioned. It’s an interesting discussion if you can bring yourself to open your mind and quit the preaching.
As we previously concluded, my panels are 4 inches wider and both yours and mine are 96 inches in height (8 ft). Thus we calculate that mine have about 400 sq in more surface area. Even so, I am aware of the potential benefits of a subwoofer. I am also aware of the negatives.
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Dear @drbond : Mainly what we listen are the developed harmonics coming from all the discrete frequencies in all the instruments in any score.
Developed harmonics " contaminate " all the frequency range and represent the MUSIC we are listen it.
That’s why is so important in any home system to tame perfectly the bass range and from here comes the subwoofers necessity/a must.
Problem is the integration with the main speakers but when that is solved then the IMD and THD goes lower than before and MUSIC starts to really shines in our room/system.
There are no disadvantages I be aware to usind subwoofers and several advantages including to the main speakers amplifiers.
In asystem with subwoofers the mid range and high frequencies are improved to levels many of us can’t imagine because with out the main speaker low bass those 2 frequency ranges are cleaned de that through the subs the bass harmonics comes with way lower distortion levels, with subwoofers disappears the bass trash developed by the bass in the main speakers: ligth comes in that room/system.
Btw, this article is a learning one about fast bass/slow bass. I took from the subwoofer dedicated thread in Agon that I started in 2005:
SoundStage! Max dB - Fast Bass, Slow Bass - Myth vs. Fact (06/1999) (soundstagenetwork.com)
R.
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The article you quote is about "woofers", not in particular about "subwoofers". You say there are no negatives. What about the required electronic crossover? It needs to be totally transparent in order to do no harm to the signal at all audio frequencies. Is there really such a thing? You need to choose crossover points and slopes that suit the drivers in question, as well. I also take the point about reproducing 40Hz, but the associated issue is what the drivers do at the crossover, i.e., the highest frequency the subwoofer (woofer in your cited article) is asked to reproduce. These considerations, especially where one is using a subwoofer to augment the response of a main speaker that can already cover the bass spectrum adequately, should be in play when one decides to use a subwoofer with an otherwise full range speaker, and if the bass augmentation is poorly implemented, then the addition of a subwoofer will be a net negative. I never met an electronic crossover that was totally transparent.
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@rauliruegas
Thanks for your recommendations. What would be the simplest and best way to add subwoofers to the system with ESL’s? I know one guy, Duke, involved tangentially with Atma-Sphere who made a group of four sub woofers, called the Swarm, or something like that. Is there something that I could just connect to the other pair of output posts on my monoblock amplifiers, or is it much more complicated than that?
Thanks.
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It needs to be totally transparent in order to do no harm to the signal at all audio frequencies. Is there really such a thing?
One can it in analogue… there is not a requirement to do it digitally.
- If one’s glasses are thick, then the DSP makes sense.
- For people that like solder and capacitors, then analogue makes sense.
Not everyone would want a Vandersteen sub, but some do. And the crossover is a key part of it:
https://www.vandersteen.com/categories/crossovers
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Dear @drbond : The swarm is nothing new and the main problem is that its subs are of low quality because they think that eliminating bass standing waves almost everything is solved and it's not exactly that way in the other side the ones that sale the swarm " scenario " almost always tell the audiophiles that an advantage is that bass is " rigth " does not matters where the audiophile is seated.
Many years ago the Harrrrman Group ( JBL, Infinity, Levinson, etc, etc,. ) made a in deep scientific research ( modeling. ) about subwoofers and they determined that the ideal number in subwoofers in home be 4 subwoofers but that 2 subwoofers were enough in a home system and for one seat position.
Subwoofers mainly is not about how deep goes but before that is the quality level has that reprodutcion bass at least to 16hz. Not all subwoofers give you the same quality level.
One very well regarded subwoofers are the JL Audio that have very good look but that inside mesurements showed at full SPL and obviously at 20hz a THD of around 6%.
The Velodyne's I own measured only 0.5% on THD thanks that the sub is checking over 18K times per second the woofer excursion.
Other quality characteristic that you have to look for is that the subwoofer be a sealed design, it does not goes down to 6hz-8hz as the ported/open-box ones ( well if the sealed one design is the " rigth " one can goes to 6hz-8hz but needs not only a bigger driver but a big box and very good construction of that box. ).
If you can find out a sealed sub with paper cone drivers the better if bass quality matters for you.
R.
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Dear @holmz : A subwoofer is a complete solution where the crossover is only an inherent and important part of any sub ( a key like you posted. ) along the box, drivers and the like. The crossover is not a second product but is part of the subwoofer it self that must has a low/high pass filters and several other functions.
Analog or digital are only options and convenience for the audiophiles to choose in between.
The subwoofer bass solution with good integration to the main speakers and room give you huge benefits. We can't talk here of disadvantages in the same way we can't say that a phono stage has the disadvantage of the RIAA eq. because it's part of the phono stage in the same way that creossover is integral part of a subwoofer.
Btw, when we have well integrated subs in our system there is no come back, we learn that we can't listen any more with out it due that helps to lower the distortions levels of not only the speakers but amplifiers too and several other advantages.
R.
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@rauliruegas
Any recommendations for a pair of subwoofers that would work with the Sound Lab ESL's? Also, since I know nothing about setting up subwoofers: is there a frequency dial that you can adjust for the precise crossover frequency? Does that mean that you then could have two sets of speakers producing that frequency: the ESL's and the subwoofers? (In which case do you need to dial out that frequency from the full range speakers?)
Thanks.
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Dear @holmz @drbond : At the end digital tech is used in almost all today subwoofers through the DSP that is the one that can gives us ( comes with a microphone. ) where in position and to our " ears " makes the " best " system/room integration.
drbond, today there are 20+ true subwoofer manufacturers so we have a wide range about. Btw, can works really fine with your SL, no problem.
This one is the today Velodyne ( mines are out of production 16 years ago. ). My way of thinking is to go with the " winner " till be outperformed:
https://www.velodyneacoustics.com/en/products/digital-drive-plus/#digital-drive-18-plus
I know by references that its DSP software is really good. The sub’s integration is critical.
You will know if your choosed sub’s are well integrated when those subs never tells you " hey I’m here " ( boom, boom, boom.... ) but only when the MUSIC is demanding asking for. When the subs are well integrated you can’t detect from where comes the bass other that when the score ask it but when the scrore is asking for the experience is just unique/marvelous and full of emotions, nothing can even it.
R.
Even this 32K dollars can't even the Velodyne THD 0.5%. Well certainly maybe the best sub out there and you need 64K :
https://www.magicoaudio.com/news/magico-titan-15-the-ultimate-powered-subwoofer-2
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Dear @holmz @drbond : At the end digital tech is used in almost all today subwoofers through the DSP that is the one that can gives us ( comes with a microphone. ) where in position and to our " ears " makes the " best " system/room integration.
^All true^. However the analogue approach is well thought with the Vandy sub system.
It may not work in a system with a different filter in the speakers as the phase could be off.
And everyone one adjusts the subs with a microphone, and either potentiometers or S/W equivalent of a potentiometers.
At least knowing that there are non-DSP approaches, and mentioning it in a thread, is not a crime. We would need a way to compare that solution to the digital one☝️to be able to say whether it is better, worse, or the same.
If one is a purist then “High Pass Filtering” (HPF) the signal going to the main speakers is often a bit “on the nose” conceptually. I have no problem with DSPs, and streaming into and out of a DAC, and conceptually into and out of a DSP. But those that do, may want to know that they’re is a non-DSP approach.
And one can then use a DSP “ONLY” on the sub band without digitally touching the signal coming out of the L/R speakers.
Dear @holmz : A subwoofer is a complete solution where the crossover is only an inherent and important part of any sub ( a key like you posted. ) along the box, drivers and the like.
^Correct^. You are not the only fellow or lady that understands what a system is.
The crossover is not a second product but is part of the subwoofer it self that must has a low/high pass filters and several other functions.
The other stuff on that web-site has the subs which rely on the HPF.
(It’s part of a system)
Even this 32K dollars can’t even the Velodyne THD 0.5%. Well certainly maybe the best sub out there and you need 64K :
It is sort of important to note that the 0.5% is meaningless in the sub band…
But it becomes pretty important in terms up HD and IMD for the higher frequencies that attenuated from the filter, but still made be created in the sub itself, and then give away their location.
The subwoofer bass solution with good integration to the main speakers and room give you huge benefits. We can’t talk here of disadvantages in the same way we can’t say that a phono stage has the disadvantage of the RIAA eq. because it’s part of the phono stage in the same way that creossover is integral part of a subwoofer.
Btw, when we have well integrated subs in our system there is no come back, we learn that we can’t listen any more with out it due that helps to lower the distortions levels of not only the speakers but amplifiers too and several other advantages.
Again… you are not first to discover ^this^.
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drbond, Duke Lejeune is the man to whom you refer, who is a friend to Ralph Karsten. His business is called "Audiokinesis". If I were to add a subwoofer, that is where I would look. Duke is the salt of the earth, a great guy and very knowledgeable about what he is doing. I am sure that Raul's recommendation for Velodyne would also be an excellent choice. But don't let Raul and Mijo make you feel inadequate. By all means, do add a subwoof, if you perceive that you need it, in your room, for your musical tastes.
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@lewm
I’ve been reading a little about sub woofers, and many sites do say that adding a subwoofer can make a real difference in other areas, such as sound stage, imaging, mid-range, etc. I’m not really sure things can sound much better, but I think it’s at least worth a trial to see if it’s any better, or possibly worse. . .
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Dear @drbond : " adding a subwoofer can make a real difference in other areas, such as sound stage, imaging, mid-range, etc. I’m not really sure things can sound much better, but I think it’s at least worth a trial to see if it’s any better..."
Yes, exist several room/system benefits but your " key " words in that statement are:
" worth a trial..."
I could think that no matters what no one could knows if needs or not sub’s till he " trials " in his room/system.
Yes, you have to test it.
R.
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Raul, Which of the current Velodyne subwoofers do you like for a moderate size listening room and for crossing over below 100Hz? Would you use the built-in electronic crossover? Pass makes or used to make an electronic crossover. I have searched for one in the used market, because I have some faith in Nelson Pass, but I have never found one for sale.
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Lew, the high pass is made it at the input of my amps ( cap/resistor ) the low pass is made it by the Velodyne electronics. Maybe you can do the same or look for a second hand Bryston croosver.
In the link I just posted you can read about 12"/15" drivers characteristics inside the same catalog models.
R.
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As I mentioned, I've never used subwoofers before. Based on limited reading, it seems that there are multiple approaches to connecting the subwoofers to a system. (e.g. All subwoofers have at least an RCA input for line level connection from your preamp or variable output on your amplifier. Do not use the record or tape output! These are fixed and you will have maximum bass at all times no matter what your main volume is set at! Some subwoofers have left and right inputs. If your preamp has left and right outputs, use two RCA cables for these. The subwoofer combines the channels inside. If your preamp has left and right outputs but there’s only one on the sub, use a Y combiner adapter. These can be had for $5 or so. Lastly, if you don’t have a subwoofer or preamp output on your amp or preamp, subwoofers such as the RELs we sell have a specific high level input which runs off your amplifier’s speaker binding posts. This cable simply piggybacks on your main speakers and does not draw any power from your amp. In this way, no matter what your system is, there’s a sub for you. )
Is there a "best" approach for monoblock amplifiers with two sets of binding posts?
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Lew, the high pass is made it at the input of my amps ( cap/resistor ) the low pass is made it by the Velodyne electronics. Maybe you can do the same or look for a second hand Bryston croosver.
In the link I just posted you can read about 12"/15" drivers characteristics inside the same catalog models.
After last week’s talk about a system I find ^this^ humerous.
Lastly, if you don’t have a subwoofer or preamp output on your amp or preamp, subwoofers such as the RELs we sell have a specific high level input which runs off your amplifier’s speaker binding posts.
There is a certain simplicity and elegance in running the sub input off of the speaker’s binding posts. Not sure if it is just REL and Vandersteen, or if there are others as well.
Is there a "best" approach for monoblock amplifiers with two sets of binding posts?
I’m not sure I understandI?
I am guessing that the speakers have bi-wire posts?
So it sort of depends on whether you 4 sets of wire pairs, or a bundled bi-wire and whether it is a single end at the amp, or if there are two set of ends… and whether they can splay wide enough to hit both sets of outputs.
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Thanks for the info, Raul. You remind me that long ago I did consider just adding a capacitor in series with the input of my main amplifier, to create a Butterworth type hi-pass filter. That still seems the least harmful way to do it. I calculated a .02uF capacitor (or two per channel for my balanced amplifiers) would do the trick for my amps, with an 80Hz flex point.
Holmz, I am no fan of the REL approach, for the reason that if you drive the subwoofer off the main amplifier output, then neither the main amplifier nor the main speaker derives any benefit in terms of reducing the workload inherent to reproducing the lowest bass frequencies. Moreover, any distortion in the output of the main amplifier is presented to the REL subwoofer amplifier at its input. Unfortunately, I long ago concluded that you cannot obtain all the major benefits of subwoofing unless you're willing to add a high pass filter on the main amplifier.
Holmz, was that "humerus" or "humorous"? And why did you find it humorous?
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@lewm
I suppose this means that your preferred approach would be to use both the XLR and RCA outputs from the pre-amplifier: one set for the monoblock amplifiers, and one set for the subwoofer.
If that’s the case, then it seems like my pre-amplifier would need a low pass and high pass cut off for the speakers to receive their proper signal and the subwoofers to receive their proper signal. Of course, another option would be to run the pre-amplifier signal through the subwoofer, which would be designed with low pass and high pass filters, and that signal would then pass to the amplifier to the ESL speakers. But I would think that this latter approach could degrade the signal going into the amplifier and ESL’s. It might be a no-win situation. . .
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Holmz, I am no fan of the REL approach, for the reason that if you drive the subwoofer off the main amplifier output, then neither the main amplifier nor the main speaker derives any benefit in terms of reducing the workload inherent to reproducing the lowest bass frequencies.
Well I am not sure what the REL approach is other than reading @Rauls words that it derives the input from line level rather than RCAs or XLRs. So it sounded like the it was similar to a Vandersteen, however the manual is a bit light light on specifics… other than that there are the speaker inputs.
But whether the main amp to speakers are high pass filtered did not pop out.
It was 30 pages and i skimmed it, so maybe I missed it… but it does seem like it is not the same as how the Vandy unit works. That unit HPF the main speakers, and then the sub rebuilds the bass back up to where it should have been without a HPF going to the main speakers.
Moreover, any distortion in the output of the main amplifier is presented to the REL subwoofer amplifier at its input. Unfortunately, I long ago concluded that you cannot obtain all the major benefits of subwoofing unless you’re willing to add a high pass filter on the main amplifier.
Well that is what I posted a while ago, and it was a high pass filter to derive that benefit that you point out.
Then the sub rebuilds the signal back to where it should be at.
One can roll their own capacitor, or use a host of HPF to do that at various price points from a capacitor to a Harrison labs one at $50 to ones at kilo$...
Holmz, was that "humerus" or "humorous"? And why did you find it humorous?
I read too much Homer in my youth, as I had a great 7th and 8th grade literature teacher. And hence the spell checker is Greek to me.
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I truly did wonder why you thought Raul’s quote was humorous. Along the way, I could not resist the anatomical pun. However, I do know that autocorrect is a bitch.
My understanding of the classic REL set up is that the signal to the REL subwoofer is derived at the interface between the main amplifier and the main speaker. That full range signal is routed to the input of the REL subwoof amplifier which has a low pass filter before its input. The REL subwoof thus augments the main speaker at very low frequencies. This method does not result in reducing the bass frequency burden on the main amplifier or even the main speaker. Perhaps I’ve got it wrong. I suppose all this belongs on another forum, but drbond seems interested, and he is the originator of this thread. Otherwise, sorry for the digression.
drbond, The classic approach is to drive an electronic crossover from the preamplifier. The electronic crossover has built in active high and low pass filters, usually with adjustments for cut-off frequencies and a choice of filter slope. Sometimes an electronic crossover can also add gain to the signal. Raul and I were talking about using an electronic crossover only for a low pass filter to the subwoofer. The frequencies above low bass would go direct to the main amplifier, but at the input of the main amplifier, all you need to do is to add a single capacitor in series with the signal. That capacitor in conjunction with the input impedance of the amplifier will act as a passive high pass filter with a gentle slope of 6db/octave. For that, you would like to have a preamplifier with two pairs of output jacks, but it's not really mandatory; you can derive a second output between the main amp and the electronic crossover you use to provide the low pass filter to the subwoof. I like this second option because the high pass signal does not have to go through a second circuit. Trade-off is something called "insertion loss"; you lose a little gain in a passive filter, usually inconsequential.
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Too late to edit my post above, but for completeness I thought I should add that an active electronic crossover is called "active" because it does add gain, to correct for the above mentioned insertion loss of any filter. The steeper the slope of the filter, the more is the insertion loss, and the more gain is added by a typical electronic crossover to compensate. The two best and most expensive electronic crossovers I know about are the Pass XVR1 and the Bryston. Pass can do 6, 12, 18, or 24db/octave slopes. A passive filter, like just adding a capacitor in series with the signal going to the main amplifier to create a high pass filter, is pretty much limited to 6db/octave, also called a "Butterworth" filter. Steeper slopes CAN be executed passively, but insertion loss goes up accordingly. You want a steep slope on the low pass filter going to the subwoof, because you don't want the subwoof contributing to midrange and treble, where it is likely to add distortion. In most cases, however, you can get by with a 6db/octave slope on the high pass filter, if your main speaker has full range capabilities. Exactly where to set the crossover points is a matter of experimentation.
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Dear @drbond : You already know that in the audio world always exist trade-offs when we want to make some room/system changes, nothing is perfect so don’t try to look for because just does not exist.
You need only a high pass because the low pass is made it by the sub’s. Now you can have that high pass with and active external crossover or you can do it at the input of your amps and for me this is the best high-pass trade-off because you add almost nothing: no added electronics, cables and input/output connectors.
The signal that goes to the amps from the CH goes directly or through the external high-pass filter and from your CH goes too directly to the subs. Btw, usually the high-pass filter setting up is in the 80hz-100 hz and you do not needs that the external/internal high-pass has additional gain because the high-pass gain is handled by the preamp. The gain of the low-pass by the sub's.
That’s it.
R.
@lewm : " I truly did wonder why you thought Raul’s quote was humorous. " . Easy, because he did not think in that way before. Seems to me that is his way of audio life kind of think because he posted twice something with no sense in reference to what I posted about sub’s, he said twice: " you was not the first person to said that " .
But where in hell posted I that " I was the first audiophile to said that " ?
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Dear @drbond : lewm posted " You want a steep slope on the low pass filter going to the subwoof, because you don’t want the subwoof contributing to midrange ..."
Normaly subs comes with 12db/18db filter shape and the users always can change the low-pass frequency that at the end the sub internal dsp will tell us and through listening tests we can confirm is rigth or we can play with the sub crossover set-up characteristics till we are satisfied with. The Velodyne low-pass shape by default is 24db ( steep as lew posted. ) but selectable and its high-pass shape is 6db. My old Velodyne low-pass filter shape " initial 12db, 48db ultimate ", is what I read in its manufacturer specs.
In the other side, adding sub’s in any room/system means too that maybe we can need some kind of different room treatment maybe not or we can find out that we need to move a little the main speaker positions.
Subwoofers per se is not a " key on hand " solution to open the " door ", we always need some kind of work for the room/system good integration.
R.
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@drbond, Are you dizzy yet? What you have here is a whole bunch of people making assumptions without a bit of first hand knowledge. The horse's mouth is right here. I have been using subwoofers with ESLs since 1979 and have been through every permutation you can imagine. I can promise you this, regardless of anything else you do you will never achieve state of the art performance out of your system without subwoofers. I can help you avoid all the mistakes I made over the years and get you set up. This is a thread about phono stages. If you want to talk about it message me.
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lewm : " I truly did wonder why you thought Raul’s quote was humorous. " . Easy, because he did not think in that way before. Seems to me that is his way of audio life kind of think because he posted twice something with no sense in reference to what I posted about sub’s, he said twice: " you was not the first person to said that " .
But where in hell posted I that " I was the first audiophile to said that " ?
You might be right… I agree that it seemed to you that it had no bearing on the topic,
Yet here we are talking about whether to use a capacitor and then how to hook the sub up, and it is a week later and you still claim that that post is not addressing some of the OP’s question on subs.
You choose to put in a capacitor, and others insert that HPF that I linked to… and then they use a powered subwoofer that is designed as a system.
At some point it is going to click as to it being a system and why I posted it.
Similarly that REL kind of clicked with me as being a bit incomplete in that is it not using the HPF between the preamp and the amp(s)… and the sub has no way to account for a dependable slope or crossover knee… so it is either too much bass or need a lot of TLC to make it blend.
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Mijo, my journey to not using a subwoofer with my full range ESLs runs through years of experimenting with subwoofers to augment other ESLs, like KLH9s, Quads, and Martin Logan CLSs, all of which really do need woofer supplementation. I built my huge Transmission Line cabinets that now supplement the Beveridge speakers back in the 70s on my nights off call when I was an intern.I’m certainly not as good a cabinet maker as you, but i do have past experience with subwoofers. That’s how I developed my distaste for electronic crossovers. (I’m sure modern ones are better.)
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Dear @mijostyn : " never achieve state of the art performance out of your system without subwoofers..."
I agree.
" without a bit of first hand knowledge....
Disagree. Some of us have that first hand experiences and in my case with different kind of main speakers including ESL and between the ESL Soundlab ones and all those experiences in different systems and always in different rooms.
The only coincidence between your room/system and the drbond one is the ESL system link. With all respect: are you trying to say that you are the " God/Emperor " of sub/ESL?
drbond wants to " test " subs and through that " tests " he will achieve the necessary firt hand experiences with to decides about.
With subs the integration to a room/system always is different in almost all, there are no rules and if you have proved and measured rules then this is a good time to share to the Agon community. Don't you think?
Subs integration is not like a change of amplifiers or phono stage or tonearm but something that each owner must have to live. Learning starts reading as he already is doing.
R.
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Are you addressing me?
No @lewm .
It appeared that @Raul was using your quote, in a way that was oblique and directed at me.
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@rauliruegas , Raul, I have been using subwoofers with ESLs since 1979. The system then was Acoustat Model Xs, with two RH Labs subwoofers, a Dahlquist crossover and Kenwood LO 7M amps. The model Xs were soon replaced by Monitor 4s which were planted on top of the RH Labs subs. Since then I have been through every permutation involving ESLs you can think of including Velodyns. Lew does not like it when I preach and here you are asking me to preach.
Subwoofer integration was a frustrating process of trial and error up until the introduction of digital signal processing by the TacT corporation which has now morphed into Lyngdorf. The first step is to determine what kind of main speaker you have and how it functions at the expected crossover point, point or line source. The subwoofer array has to match this radiation pattern. Subwoofers are always more efficient against walls and in corners. Rule #1 is never use just one subwoofer, two is the minimum.
The trick is to use the highest crossover point possible without allowing the sub to creep into the midrange. This requires slopes higher than what is practical for analog crossovers. I use 100 Hz at 48 dB/oct. The more bass you take away from an ESL the better it performs. It is critical for time and phase to match the main speakers. This is a breeze to do digitally and virtually impossible in analog fashion.
There are many great subwoofer drivers out there now. The real problem is the enclosure. Any subwoofer driver producing 20 Hz at 90 dB is going to make the enclosure shake at 20 Hz. Any shaking of the enclosure is distortion. To counteract this smart designers place identical drivers at opposite ends of the enclosure running in phase so that their Newtonian forces cancel out. This is called balanced force design. Magico, Martin Logan, Kef and MS tool make balanced force subwoofers. Increasing the mass of the enclosure does not stop it from shaking. The next problem is making the enclosure entirely non resonant at subwoofer operating frequencies which means very stiff walls made from critically damped materials. Magico uses aluminum, Kef uses composite and I am not sure what ML uses, probably MDF. I use 1.5 inch thick maple plywood. Plywood is stiffer than MDF. It is more expensive and harder to work with. Keeping the enclosure as small as possible helps in this regard. Play a loud bass heavy song and put your hand on the sub enclosure, any shaking or vibration you feel is distortion. You should feel none.
The low pass filters most manufacturers use in their subwoofers are little more than a joke. To tune a system correctly you need a two way crossover with crossover points and slopes adjustable from the listening position. You should not be able to sonically separate or locate subwoofers. They should seem invisible except for the added bass they provide. The most significant feature is the reduction of distortion in the main speakers. With two or three way speakers this reduction occurs only in the range handled by the woofer but in full range ESLs it applies to the entire frequency range and is even more obvious even if Lew disagrees.
Finally, smaller drivers are not faster. They have to move farther and faster to produce the same note at the same volume creating more distortion along the way. Larger drivers produce bass with less distortion. You can produce the same effect with multiple smaller drivers. It is a matter of how much surface area you have in operation. To produce 18 Hz with authority in a 15 X 25 foot room with reasonably low distortion you need at least two 12" or four 10" drivers. There is a limit in terms
of size. Larger heavier cones are more difficult to control and can wobble creating distortion. I have seen strobe light videos displaying this. Where the limit is I have no idea. I think in the home situation drivers larger than 15" are unnecessary, just use multiples if you need more. The system I am building now uses eight 12" drivers, two in each enclosure.
Room control is a nice addition for subwoofers but it does not excuse poor acoustic management of the room. Room control (really speaker control) can stress amps and drivers otherwise and cause more harm than good. This is another reason for using multiple subwoofers. Multiple subwoofers in different locations evens out the bass response within the room.
Bedtime
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I truly did wonder why you thought Raul’s quote was humorous. Along the way, I could not resist the anatomical pun.
@lewm I liked the pun. So you get a point.
(But let’s try and resist using digital in an anatomical pun please.)
The two best and most expensive electronic crossovers I know about are the Pass XVR1 and the Bryston.
I assume you mean “electronic” as in solder and parts?
The DEXQ is more like a MiniDSP, Lyngdorf or Trinov, but for more a 2-channel.
It is likely overkill, but subs, and bi-wire binding posts, then it has some allure that could allow it to be used as a 3 way XO.
It is a digital solution and the pricing reflects it as being digital.
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Hmmm…this subwoofer project is looking complicated:
it seems like an ideal approach would be an in line high pass filter after my pre-amplifier, but this would have to be an analog filter, correct?
(I can see myself reacting to a cello that sounds like it’s in one place for the higher notes, and another for the lower strings/notes…)
…or replace my pre-amplifier, which I really enjoy listening to, with a digital pre amplifier that has filters built into it…which I am averse to do…
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Dear @mijostyn : " and here you are asking me to preach..."
Not really that you took my post to preach is only because you like to show you about. Fine with me and if you read in reality you only repeat what other posts already touch it ! !
My post was to say that you are not the only audiophile with good knowledge and experiences on sub’s/ESL. That’s it.
R.
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Dear @drbond : Your amps is a design with tubes at the input well it’s down there ( a good technician that knows where in that stage and calculation for the cap is need it. ) where the high-pass could goes. No you don’t need digital .
If after your tests you do not like it you always can return as the begin.
"" this subwoofer project is looking complicated.. ""
No, maybe some of our posts made that " looks " complicated but it’s not at the level you are thinking and at the end is a room/system tests .
After those tests you will know where to go. Btw, for your subs test it’s not need it that you go with the 18" Velodyne model, you can make that job with the 15" woofer model.
R.
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Just my thoughts but would like to see this thread titled "Phono Stage upgrade to complement Dohmann Helix One Mk 2" get back on track. Talking about subs is not that relevant to many.
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@rauliruegas
By complicated, I was referring to the act of installing an in-line digital high pass filter after the pre-amplifier, which would require an ADC and then a DAC before the amplfiier. . . and not sure how it would then affect the SQ, which is superb presently through the Ypsilon PST-100 Mk2 SE pre-amplifier.
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drbond, There is no need to overthink this or to overspend, either. There is absolutely no need to change your preamplifier, either. The very simplest thing to do is to buy a high quality Velodyne or other reputable brand subwoofer. These typically have built in to their electronics a pretty good electronic crossover which allows you to choose cut-off frequency for the high and low pass filters, and slope for high and low filters, as well as a level control so you can balance the two. This is done electronically using a microphone and computer programming that is built into the subwoof. It's quite amazing where the technology now stands. For you as a novice, this is the path I would recommend, if you are willing to spend the bucks on a very good subwoofer. If on the other hand you want to use a passive high pass filter with a 6db slope and use only the low pass filter built into your new subwoof, I can calculate the value of capacitance you need to effect a crossover at a particular frequency of your choosing, if you supply the input impedance of your amplifier. Since you have an Atma amplifier (if memory serves), I already know the impedance is likely to be 100K for SE mode and 200K ohms for balanced. Typically you would use a cut off below 100Hz. At those frequencies (and lower is better), bass is non-directional. If you're crossing over below the primary tones of the instrument, then you would have absolutely no sense that the musical line is jumping from the main driver to the subwoof. I wonder how Raul and Mijo feel about the need to use a stereo pair of subwoofs vs a single subwoof. My bias would be to use a pair of modest size (e.g., 12 inches) or one of large size (15-18 inches). The lower you crossover, the less would be the need for a stereo pair, by my own estimation. You could crossover at 60Hz with our speakers or maybe 80Hz.
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