Bass Response

[Thunderbox]

Have you heard Mahler Symphony 2 performed by a world-class orchestra in a world-class symphony hall (i.e., no sound reinforcement system)? Saint-Saens Symphony 3 (Organ Symphony)? Do you regularly attend live performances of large-scale orchestral music?

If you routinely listen to large-scale orchestral music performed live in a world-class symphony hall, and you have a speaker with two 4” drivers that can play a modern hi-res recording of such compositions (i.e., a modern recording with uncompressed dynamics, such as a recording captured and delivered at 24bit/192kHz) - at live concert sound levels – with no compromise in frequency range, and no compromise in dynamic range – i.e., creating the illusion of being in the symphony hall – then I’d like to hear that speaker system with the two 4” drivers.

OTOH, if you listen to music with little dynamic range – and/or recordings with limited dynamic range (e.g., LPs) – that’s a different story.

P.S. Your following comment is IMO unprofessional, and represents IMO an unacceptable ad hominem attack: “Better to remain quiet and be thought a fool, than to open your mouth and remove all doubt.“

You may be correct and I may have stepped over the line. As far as getting the live orchestra sound from a stereo system it just isn't going to happen with 4' or 30" speakers unless you have a speaker in place where each instrument is supposed to be playing.

 

[SaturationPt]

You may be correct and I may have stepped over the line. As far as getting the live orchestra sound from a stereo system it just isn't going to happen with 4' or 30" speakers unless you have a speaker in place where each instrument is supposed to be playing.

You need to listen to a proper system set up properly. The imaging from two main speakers creates a perfect 2-D image due to the delay and attenuation from the near channel to the far channel, it's the reason that stereo exists.

 

[Grenadeslio]

You need to listen to a proper system set up properly. The imaging from two main speakers creates a perfect 2-D image due to the delay and attenuation from the near channel to the far channel, it's the reason that stereo exists.

2-D? Well many here find if set up properly it's possible to get a holographic 3D image with only 2 speakers, with width, depth, and height.

A good example of a record that will demonstrate this is Sly & The Family Stone I Want to Take You Higher live on the Woodstock album. Set up properly it should be easy to tell when he switches between the sound reinforcement system and the public address speakers set up high and to the extreme sides as he coaches the audience.

 

[SaturationPt]

People say 3-D, and although I feel that I can sense height differences the science doesn't support it, so I am happy telling people 2-D.

Even the 2-D soundstage is somewhat false unless one's system is set up with no reflelctions / no 2nd-arrival sound, no turntables creating crosstalk, etc., etc. but the pure and the enjoyable aren't always the same thing, ... I've been way down the perfect and pure route and although it is great for bragging rights, there are some things that sound better to the human ear and brain.

 

[Grenadeslio]

People say 3-D, and although I feel that I can sense height differences the science doesn't support it, so I am happy telling people 2-D.

Even the 2-D soundstage is somewhat false unless one's system is set up with no reflelctions / no 2nd-arrival sound, no turntables creating crosstalk, etc., etc. but the pure and the enjoyable aren't always the same thing, ... I've been way down the perfect and pure route and although it is great for bragging rights, there are some things that sound better to the human ear and brain.

Again, try the song off the Woodstock album "then" get back to me.

 

[enginedr]

You need this and a pair of good stand mount speakers
http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

 

[TSmith8605]

Have you heard Mahler Symphony 2 performed by a world-class orchestra in a world-class symphony hall (i.e., no sound reinforcement system)? Saint-Saens Symphony 3 (Organ Symphony)? Do you regularly attend live performances of large-scale orchestral music? . . .“

Yes (several); yes, (in fact in Feb 2020, the last concert I heard before the shut down - it was magic; and yes.

I also have a collection of (mostly Mahler) SACDs recorded in the same hall by the same orchestra and conductor and have compared those to live with a little over 1-hour time separation. Turns out that the vintage system - but with the MCD500, comes closest to the real deal in terms of voicing and imaging. It seems that so-called McIntosh house sound sorta is like the real deal. The Acoustats image but they really don't do so accurately and the voicing is skewed with too much upper midrange, I guess. But with the Acoustats in a very acoustically-dead room, I can hear the sound of the hall itself and I recognize the ambiance although it's in the wrong place - in front of me not all around me.

The Original Large Advents do a credible job with the bass drum (the lowest note I hear from an Orchestra other than the organ). None of my speakers can get the lowest organ notes.

So I think of a sub woofer as a device to fill in that bottom octave (20 Hz to 40 Hz) for speakers that don't reproduce that - and most speakers do not. My Acoustats are hybrid with electrostatic panels run about 100 Hz and a satellite woofer box that goes down into the 30s. Some might call that a subwoofer but I call it the woofer.

But what I have been thinking about for awhile now is to replacing that satellite woofer with a subwoofer that covers 100 Hz to 20 Hz and use EQ to help deal with room modes below 100 Hz. I am also not a fan of adding any processors to the signal path, but don't think that would be an issue if I bi-amp and the processor is only in the woofer's signal.

I have a 14' x 14' room so have some real bass mode issues. In fact, I stuck my Magnepans in this room and the bass - mid bass was so overwhelming as to make the whole thing unlistenable. So quickly I moved those to their intended 15' x 20' room where they work fine and reinstalled the 'stats in the small room.

Right now, I have an attenuator on the woofer amp that allows me to lower or raise the woofer level as shelf below 100 Hz (rather than a roll off) relative to the panels and I adjust that depending on the recording. That makes the system listenable in this room and goes a long way to dealing with room modes.

But I still don't have a flat response below 100 Hz. So a first step, might be to stick something like an MQ107 in front of the woofer amp and try to tune it to tame specific room modes below 100 Hz. Then maybe get a better woofer to keep up with the MC452-driven panels. I don't have proper test equipment but I think I could get things a lot closer by making measurements with an SPL app on my phone and my audio oscillator and writing down the results by hand. Would be time consuming but does this need to be perfect? If I have ,say, a 9-dB peak at say 50 Hz and I drop it either 10 dB or 6 dB, I think it will be much better even if I'm off by a dB or two.

But it may be time replace the old 'stats and if I do, I will require a speaker that allows bi-amping below 100 - 200 Hz. I caught a presentation by Richard Vandersteen at the RMAF last fall and he was saying the same thing and he makes his speaker this way. The higher-end speakers have self-powered woofers and built-in EQ (for just the woofer) that the user can set up - and the cross over is at 200 Hz (I think) . I asked about the set up procedure to measure the room and he said an iPhone will suffice. He also said something I had not thought about, that he had experimented with digital processing for the woofer EQ but could never get the integration with the rest of the (unprocessed) band correct because of the digital processing time delay. So he uses analog EQ on the woofer.

So with this bi-amp and EQ only below 100Hz or 200 Hz approach allows no need to add processing to the upper ranges that many people (including me) don't like because of added noise and distortion but still be able EQ room modes in the bass. In fact, I've heard that EQ of the mid and higher range does not work well basically because the frequency response peaks and dips are different for the direct and reflected waves - this theory says that the frequency response needs to be flat, or at least the same, in all directions from the speaker.

So, one idea I had for new woofers for my 'stats, is a pair of ML1s running below 100 Hz and corrected with maybe an MQ107 to get powerful, flat (er) base response down to 20 Hz in a 14' x 14' room.

I guess OP is gone, but these are my ideas about a speaker system for a 14' x 14' room.

 

[SaturationPt]

A couple of my thoughts.

I have mixed feelings on dipole speakers such as Magnepan and Acoustat, I have had two series of Magnepan (can't recall which), Acoustat 1+1s, ML, and still have (in a closet somewhere) my Quad 63s and a pair of my favorite speakers: the Heil-equipped ESS AMT Monitors. I do understand and in many cases enjoy the music from speakers that rely on 2nd-arrival sound from the rear to create the "ambiance ... in the wrong place" you mentioned and that these create (not reproduce). It can sound wonderful, but it isn't real.

It's a case of the distortion and addition to the program sounds creating the illusion of lots of space, a concert-hall, a type of reverb that much HiFi equipment (including the venerable Dynaco PAS preamps) offered as an option to add "presence".

I will likely get some flames from this, but there is NO WAY that a delayed 2nd-arrival sound from the back of a speaker can be in any way considered an accurate reproduction. Dipole speakers sound good, but not accurate.

Regarding using an analog processor to run bass-only, like any crossover you will need to ensure that the frequencies going into your bass unit (or sub or whatever you want to call it) is not being produded also by your full-range system. Unfortunately, an analog crossover will create phase-distortion / phase-shift, a higher order crossover has a sharper cutoff but more phase-shift at the cutoff. You will have some overlap at each crossover point, if not engineered well this will smear your imaging, not as much at low frequencies but more at mid-high frequencies. At any rate you are going to process both your bass and your remaining frequencies to avoid overlapping the entire bass range, so you have added processing either way, ... an equalizer is a processor. I would prefer a good DSP for this job to reduce phase distortion at the crossover points.

 

[E-Stat]

My Acoustats are hybrid with electrostatic panels run about 100 Hz and a satellite woofer box that goes down into the 30s. Some might call that a subwoofer but I call it the woofer.

You need more panel area! One per side really isn't enough.

Four, however, worked fine with the 2+2s I used for many years. The current two panel 1+1s in the HT do first octave but not at particularly high levels. They are supplemented by dual subs below 80 hz. That frequency is higher than *necessary*, but proved to provide the most linear measured response in the family room in conjunction with some parametric EQ to attenuate huge room peaks from 55-60 hz.

 

[c_dk]

You need more panel area! One per side really isn't enough.

Four, however, worked fine with the 2+2s I used for many years. The current two panel 1+1s in the HT do first octave but not at particularly high levels. They are supplemented by dual subs below 80 hz. That frequency is higher than *necessary*, but proved to provide the most linear measured response in the family room in conjunction with some parametric EQ to attenuate huge room peaks from 55-60 hz.

Did you save and can you post the empirical data you collected?

 

[TSmith8605]

I agree about your comments on dipolar speakers and so for the 'stats and the fake imaging implied by rear reflections. I have a lot of sound absorption stuff behind the 'stats and to the sides and on the side walls ceiling and carpet. The 'stats are also flat, so point right at the sweet spot, again minimizing room reflections. A lot of people would say I have really overdone room damping but this does work to the extent that I hear the ambiance that is on the recording much more than in my own room and to a certain extent, I do listen seemingly well into the detailed sound on the recording. With this set up, you only hear sound stage depth and ambiance if it's actually on the record. But image height is kind of a problem when compared to live orchestra. I mostly use my 'stats for rock and roll and TV / movies.

For the Maggies, I just set them up as intended by Magnepan and really do like the sound and the imaging is actually pretty good. I also did nothing to treat that room except for a carpet. Completely different approach. Very nice for quieter music like Jazz, folk, classical, etc. They are set up exactly were the old Advents were and do edge out the old Advents but not by much.

So two completely different approaches / theories both actually fun to listen to.

If I replace the Acoustat satellite woofer with a another sub woofer, I will use the same simple 1-pole crossover low pass for the woofer as Acoustat used on the current woofer and will continue to use the speaker's own crossover (between the amp and speakers) on the panels - so no processing would be used on the panel high-pass signal path. The active low pass processor and EQ would only be driving the woofer amp. This exercise would like integrating a subwoofer with a speaker that only goes down to 100 Hz, which may or may not be successful.

If I get something new, like a Vandersteen speaker, I will rely on their crossover design, though I think in particular with Vandersteen, it would hook up the same way I'm thinking in the paragraph above - i.e. nothing between the preamp and the amp driving the upper range speakers.

What won't work in the 14' x 14' room will be a speaker over which I don't have independent EQ control below 100 - 200 Hz.

And to my mind, if you have for example small stand speakers and a satellite woofer that goes down to may 45-ish Hz, I would call that a woofer that would require a sub woofer to cover the range from 20 - 45 Hz for those who want to here that range. Most people call it a sub woofer because it's in a separate box.

 

[TSmith8605]

Friend of mine has 2+2s and I've heard them a lot. But I think they would overwhelm my small room.

 

[E-Stat]

Did you save and can you post the empirical data you collected?

What I do is try perhaps fifteen to twenty variations of low pass/high pass, sub level and attenuator settings. Don't keep resulting curves for every trial but do have third octave results:

Family room has null centered around 100 hz and my options for placement are more limited.

 

[E-Stat]

I will likely get some flames from this, but there is NO WAY that a delayed 2nd-arrival sound from the back of a speaker can be in any way considered an accurate reproduction. Dipole speakers sound good, but not accurate.

No flames, but disagreement. I use diffusion in the rear and sides in the main system to control the rear wave with the mains out slightly more than eight feet from front wall for optimum measured bass linearity. As for dipole "accuracy", you're also disagreeing with the late Sigfried Linkwitz.

When I listen to wifey playing her baby grand, the sound character doesn't radically "disappear" when I walk behind it. I suspect the timpani player hears the orchestra much as we do on the other side.

I use recordings of live, unamplified music as my reference and would not prefer artificial sounding anything.

 

[E-Stat]

Friend of mine has 2+2s and I've heard them a lot. But I think they would overwhelm my small room.

Your primary challenges are the square dimensions reinforcing room modes and (most likely) the inability to get the panels away from the front wall. A mentor of mine taught me the "Rule of Thirds" which has served me well. That suggests the optimum distance to front wall would be ~ 56" or nearly five feet.

Lucky lad I am, the big stats live in a 26 x 15 space (nearly golden ratio) with some asymmetric additions due to the dormers at both ends of room. The rear depth is split due to the dormer location.

 

[c_dk]

What I do is try perhaps fifteen to twenty variations of low pass/high pass, sub level and attenuator settings. Don't keep resulting curves for every trial but do have third octave results of final result:

Family room has null centered around 100 hz and my options for placement are more limited.

Do you have the response curves for each channel individual? And full range?

 

[E-Stat]

Each individual channel? No. I always listen to both simultaneously.

The full range response of the smallish 1+1s is insufficient for good first octave response at desired output levels due to diaphragm excursion limits. Most importantly, one must carefully blend the output of the mains and subs for the most linear combined output.

That's where the alchemy comes into play.

 

[SaturationPt]

No flames, but disagreement. I use diffusion in the rear and sides in the main system to control the rear wave with the mains out slightly more than eight feet from front wall for optimum measured bass linearity. As for dipole "accuracy", you're also disagreeing with the late Sigfried Linkwitz.

When I listen to wifey playing her baby grand, the sound character doesn't radically "disappear" when I walk behind it. I suspect the timpani player hears the orchestra much as we do on the other side.

I agree, as I walk around our piano, it has sound all around. However, if I were to listen, I only hear the sound once, I'm only in one position so I would hear no reflected sound (except in my case there is a wall beside the piano, ... but in a concert usually not). With dipole you have in your setup 56" from the back of your speakers to the wall, another 56" from the reflective surface back to the piano, so that reflected sound is 112" delayed from the direct sound coming out of your speakers. Calculate the ips speed of sound into that you have your time delay. Fortunately planar electrostats toed-in will hit at least two walls before returning to you, serious attenuation should occur. That and your diffusion mentioned, ... I'm sure I'd like to hear your setup.

Tsmith a 14' square room can be a tough room as E-Stat mentioned, I can't imagine you'd get it right without some room treatments. The good part of highly-directional speakers like your (planar) Acoustats is that the high-energy of the sound is fairly focussed, makes it easier to find and treat the "hot-spots".

 

[E-Stat]

I agree, as I walk around our piano, it has sound all around. However, if I were to listen, I only hear the sound once, I'm only in one position so I would hear no reflected sound (except in my case there is a wall beside the piano, ... but in a concert usually not).

Do you recall that Dr. Bose measured 11% direct output and 89% reflected response at Boston Symphony Hall from his listening position?

With dipole you have in your setup 56" from the back of your speakers to the wall, another 56" from the reflective surface back to the piano, so that reflected sound is 112" delayed from the direct sound coming out of your speakers.

Last time I checked, "more than eight feet" in my setup works about to be about 100" in either direction.

Calculate the ips speed of sound into that you have your time delay. Fortunately planar electrostats toed-in will hit at least two walls before returning to you, serious attenuation should occur. That and your diffusion mentioned, ... I'm sure I'd like to hear your setup.

Come on by!

Tsmith a 14' square room can be a tough room as E-Stat mentioned, I can't imagine you'd get it right without some room treatments. The good part of highly-directional speakers like your (planar) Acoustats is that the high-energy of the sound is fairly focussed, makes it easier to find and treat the "hot-spots".

It was with that dimensions I calculated the thirds to be approximately 56" distance to front wall. Once again, I'm thinking they are much closer.

 

[damacman]

hmmmm ... 1/9 = 11% ...