It's all a balance of compromises. DSP just allows you to compromise in different ways.
Simply applying DSP to a "classically"designed speaker is unlikely to show you what DSP can do.
For example, my little OB's measure flat to 40Hz in a way that would be difficult to achieve passively.
It's much easier to use low-QTS drivers on an OB with DSP. Some would argue that low-QTS drivers improve the sound more than the DSP degrades it.
Units like the MiniDSP are cheap enough that you can justify them merely as a development tool. Then you can decide whether ASP is worth the effort.
Cheers,
Mike
Simply applying DSP to a "classically"designed speaker is unlikely to show you what DSP can do.
For example, my little OB's measure flat to 40Hz in a way that would be difficult to achieve passively.
It's much easier to use low-QTS drivers on an OB with DSP. Some would argue that low-QTS drivers improve the sound more than the DSP degrades it.
Units like the MiniDSP are cheap enough that you can justify them merely as a development tool. Then you can decide whether ASP is worth the effort.
Cheers,
Mike
Hi,
coupled rooms behave like coupled air-volumes, similar to a BR-cabinet.
It seems that almost always the lowbass performance suffers in that they suck so much bass-energy.
You´ll probabely need a subwoofer system that can generate alot of acoustic power, hence think big or think multiples.
I´d guess that a dipole subwoofer will not be putting out enough power in such a room situation unless Your listening position is in close nearfield.
The dipoles basses may be used to advantage in the upper bass and lower-medium range though as kind of a filler-driver concept.
They may then be supported by ´true´ suwoofers, covering the range below 50Hz-60 only (prefferaby below the lowest room modes).
jauu
Calvin
ps. SL is Siegfried Linkwitz the Mercedes Benz in Audio
He has written some really must read stuff about Dipoles and their EQuing.
see His Website
coupled rooms behave like coupled air-volumes, similar to a BR-cabinet.
It seems that almost always the lowbass performance suffers in that they suck so much bass-energy.
You´ll probabely need a subwoofer system that can generate alot of acoustic power, hence think big or think multiples.
I´d guess that a dipole subwoofer will not be putting out enough power in such a room situation unless Your listening position is in close nearfield.
The dipoles basses may be used to advantage in the upper bass and lower-medium range though as kind of a filler-driver concept.
They may then be supported by ´true´ suwoofers, covering the range below 50Hz-60 only (prefferaby below the lowest room modes).
jauu
Calvin
ps. SL is Siegfried Linkwitz the Mercedes Benz in Audio
He has written some really must read stuff about Dipoles and their EQuing.
see His Website
I am firmly opposed to multiple subs.
I greatly prefer 2 subs, one per channel.
The goal of flat response is less important than "time alignment" to me.
I want the event spaced in my soundfield so that I can not hear that A) there is a speaker on in the room and B) certainly that a sub is running.
(the argument about "bass being mixed mono" is specious)
Corner placement is highly problematic. Bad idea in MOST cases. No, terrible.
Why?
Because you have to load the room.
This is the same problem that Klipshorns have. In some rooms they are really wonderful (in terms of LF) and in others they're simply horrid. So, the results are entirely room dependent. Not a good plan for a design.
Once in the corner, you would have to delay the mains substantially to get the timing relationships back - which I suppose is possible with DSP today, and so may change this objection. But I'm not sold on the idea that ANY present day DSP box is sufficiently clean to reach beyond a certain level of overall sonic quality. (ymmv)
I strongly challenge the idea that one can actually achieve a truly excellent result in terms of sonics using DSP, Class D amplification, or MOST speaker systems... of course YMMV, and many would disagree.
So, as koja suggested, it is critical to define the objectives and in light of the physical constraints of your space before trying to figure out which parts will make a system that works for you... which is still not easy or simple, or without making some educated guesses - some of which (or all) may prove to be NG in the end.
_-_-
I greatly prefer 2 subs, one per channel.
The goal of flat response is less important than "time alignment" to me.
I want the event spaced in my soundfield so that I can not hear that A) there is a speaker on in the room and B) certainly that a sub is running.
(the argument about "bass being mixed mono" is specious)
Corner placement is highly problematic. Bad idea in MOST cases. No, terrible.
Why?
Because you have to load the room.
This is the same problem that Klipshorns have. In some rooms they are really wonderful (in terms of LF) and in others they're simply horrid. So, the results are entirely room dependent. Not a good plan for a design.
Once in the corner, you would have to delay the mains substantially to get the timing relationships back - which I suppose is possible with DSP today, and so may change this objection. But I'm not sold on the idea that ANY present day DSP box is sufficiently clean to reach beyond a certain level of overall sonic quality. (ymmv)
I strongly challenge the idea that one can actually achieve a truly excellent result in terms of sonics using DSP, Class D amplification, or MOST speaker systems... of course YMMV, and many would disagree.
So, as koja suggested, it is critical to define the objectives and in light of the physical constraints of your space before trying to figure out which parts will make a system that works for you... which is still not easy or simple, or without making some educated guesses - some of which (or all) may prove to be NG in the end.
_-_-
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Agree. Like to read more Mike posts at DIYaudio.
While there's quite a diversity of opinion in this thread, nobody says DSP is bad, only maybe dubious benefit. Since it is cheap to buy a miniDSP or Behringer....
Ben
Multiple Subs?
I don’t pretend to understand most of the physics behind theories by Todd Welti, Earl Geddes and Duke LeJuene for the use of multiple subs And there are some disagreements among one or two of these designers as to approach and/or technique. For example, Welti and LeJeune say identical subs; Geddes says subs of different sizes. In any case, I think it’s quite likely all three would agree, that in addition to eliminating room modes, their other goal was to make any pair of well designed and placed subs even less noticeable by adding more subs. Wasn’t this one of your requirements for using any subs? And this I’m reasonably sure, is what they claim will (depending on the room) usually be achieved by adding a second pair of subs, if space permits, naturally. Welti’s measurements suggest placement options for a given number of subs. https://www.harman.com/sites/default/files/white-paper/12/11/2015 - 06:12/files/multsubs.pdf Likewise, Geddes’ white papers will likely offer added insights into the apparent benefits of multiple subs, though his approach may differ somewhat from Welti’s or LeJeune’s. Distributed Bass A simple execution for the distributed bass concept. Article By Jeff Poth Evidently, more than a few ears seem to find what multiple subs can do for most any listening environment to be quite pleasing, even after some amount of acoustical room treatments. AudioKinesis SWARM: The Ideal Sub System? - Mike Currie - Planar Speaker Asylum As for stereo bass, I’d certainly be the last one to short change its value, if many recordings, in fact, possess it. But do they? The survey that Duke referred to says that recordings with stereo information below 80Hz are very rare, if they exist at all. Swarm Invasion target="_blank">Swarm Invasion FWIW, I’ve no business affiliations with any of these designers.
1. not much disagreement from anybody these days on that point
2. not much support for stereo bass and the benefits of multi-sub mono are substantial.
Not much debate on these points.
But you can't have subs spread around unless the crossover is steep and the sub output is clean. if so, no problem even going to 130 Hz on music.
B.
My post lists my reasons following the word,"Specifically....."Really? Care to define "good"?
More needed?
Ben
My pair of Rythmik 12" sealed servo subs use 12 or 24/octave crossovers Rythmik Audio servo subwoofer 12" F12SE Signature Edition - specifications Are these sharp enough?
And their servo controlled design would very likely deliver clean articulate bass. Rythmik Audio • Servo subwoofer products
Plus, I would think that whether you’re doing late night listening or cranking it up a bit (not that I can or even would really do much of the latter in a two bedroom condo) using four of these subs (in mono) would help maximize frequency response and minimize distortion.
I disagree - multi sub mono is like having blender, everything is smooth?
So let's debate?
_-_-
I don't want to be in the middle of this good thread.
Do you mean, "Specifically, any sub in a room benefits from EQ and no feasible way at low freq except DSP.
You need sharp crossovers to keep stereo image in the ESLs and out of the subs."
Systems that had bad room nodes were OK 10 yrs ago, but no need to tolerate them today. Yes, many of us used parametric EQ to shape low freq response long ago. But DSP is the smart path today.
Yes, you can have any slope you want with analog circuits. But see previous sentence.
Ben
The question is: what clues are revealing the location of the sub(s)?
Do the math. With or without the crossover, you have harmonic distortion and noise and maybe natural noises coming out of the sub(s). Distortion showing up at 120, 180, or 200 Hz will be monumentally more noticeable than the fundamental note.
About slope, again, do the math. 24dB/8ave should be OK, but not slower slopes. Same as previously, anything that slips through the crossover will be much easier to hear.
BTW, had a Klipschorn sub in a corner for decades. These are very clean, use clean amps, and the driver is buried deep inside so less noise and crap makes its way to the mouth and your ears.
Ben
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We've been over that many times in other threads. Some people are better able to locate low sounds than other people. Yes, I have blind tested this.
And you're talking about subs again. Isn't the topic of this thread DSP for OB and ESL?
I have no polite way to respond to your claims of hearing things others can't except to point out there are lots of ways to conduct a cognitive "experiment" and get artifactual results.... going back to famous "Clever Hans" the horse skillful in arithmetic.
Do you know a lot of ESL users who do not have (or need) cone subs? Or
Ops?
B.
I presume you mean does he know a lot of ESL users who have (or need) cone subs? Well, maybe not a lot of ESL owners, but I just met one yesterday. https://forum.audiogon.com/discussions/review-quad-57 ct0517 bought his first pair of Quad 57s. After settling on what he said was the amp “made for the 57s” (maybe he’s right?), he did a few placement tweaks. Then he finally raised them to what looks like a good 20” or so above the floor. https://photos.google.com/share/AF1...?key=ZkJTeDBrTWFiT1ozdlY4VmQzUHpQZmo3cER2WE9n
He claimed that he actually got rid of that hellish “head in vice” 1 foot sweetspot that these “giant headphones” with the midrange to die for force you into. I surely hope he succeeded in this because it looks like it's either the 57s or a custom built pair of OBs for me. And I don’t think that I can live without an amply sized 3D soundstage.
Of course, in addition to its high end that rolls of somewhat quickly, the 57s only go down to 40Hz, less if you crank them, which I wouldn’t lest they (or my EARS!) get damaged, which is not hard to do. And yes, as shown in the photo he does indeed use a pair of Dynaudio sealed subs. Those Dynaudio models are excellent, but my pair of Rythmik 12" sealed servo subs would likely keep up with the 57s even better. Then again, there are Danny Richie's servo-controlled dipole "cone" subs, if you think they would work better with the Quad 57's Audio Asylum Thread Printer
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Of course - and you are correct to mention it. But I understand those traps, and have set up experiments to avoid them. Nothings perfect. This has been well covered in other threads, and is off topic here.
I do not. My main ESL experience is with double stacked Quad 57 panels. Even double stacked, they need a sub. I have built and heard a number of OB speakers that did not need a sub. But so what? That isn't the subject of this thread. You are talking about using DSP with subwoofers, this thread is about using DSP with ESL or Open Baffle. Not the same thing.
Should we change to the topic of the thread to "Integrating subwoofers using DSP"?
Putting the 57s up on a stand per the picture means that there will be a substantial floor bounce dip in the response. This happens with ALL speakers, not just ESLs. So the sub will need will likely want to fill the dip area too... ymmv.
Nothing you can do to a flat HF radiator is going to cause the polar response NOT to narrow with increasing frequency. So, no matter what there will be an on axis "boost" in the very highest highs, compared with off axis. I've found this to be the case with almost all speakers, with a few minor exceptions.
That can be handled by toeing the speakers in so that they cross in front of the listener... which works well, but somehow not many people do. One reason may be aesthetics - it may not "look right" to some?
Acoustats do not need a sub, generally speaking, if you have model 3s or larger, and properly placed in the room. They have more bass than many dynamic speaker systems. But they are an exception in the ESL world.
Nothing you can do to a flat HF radiator is going to cause the polar response NOT to narrow with increasing frequency. So, no matter what there will be an on axis "boost" in the very highest highs, compared with off axis. I've found this to be the case with almost all speakers, with a few minor exceptions.
That can be handled by toeing the speakers in so that they cross in front of the listener... which works well, but somehow not many people do. One reason may be aesthetics - it may not "look right" to some?
Acoustats do not need a sub, generally speaking, if you have model 3s or larger, and properly placed in the room. They have more bass than many dynamic speaker systems. But they are an exception in the ESL world.
But my pair of mains go down to 70Hz. (And if I also get the Quad 57s or the OBs with AE Dipole 15 woofers, they go down to 40Hz and 30Hz, respectively). And since the human ear becomes less sensitive as frequency decreases, how many would hear harmonic distortion from subs that only begin to kick in at around 60Hz?
Furthermore, if you're talking about distortion from each sub's cone excursion and/or from each sub's Class AB plate amp, since 4 rather than 2 subs would be used, each cone and amp need to be driven less to produce the desired total SPL to fill the room. So wouldn't that produce less distortion overall?
"go down to 70..." or it would be better to say, "must be crossed over at 140 Hz in order to be credible...".
You are "climbing" the very steep Fletcher-Munson curve. Even a bit of distortion or noise at harmonics of 40 Hz will be far more easily heard. And the power going into a sub at a 40 Hz fundamental is very large in order to have some impact on your hearing so that is boosting the harmonics too.
Listeners are not greatly bothered by moderate harmonic distortion when present on music... and might really love the "warmth" of tube amps. But a different question when we are talking about scrambling the stereo image and revealing sub locations around the room.
B.
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