David, looking at low frequencies that way doesn't help. The situation is dominated by the room and not by the source nor its type or crossover). You have to look at the steady state response in situ with a RTA (1Hz resolution) and white/pink noise (depends on the characteristics of the RTA).
I'm using white noise with this FFT analyzer: FFT Analyzer
At the moment there is no easy way to address low frequency problems. There might be a solution with upcoming AVRs but we're just not there yet.
I'm using white noise with this FFT analyzer: FFT Analyzer
At the moment there is no easy way to address low frequency problems. There might be a solution with upcoming AVRs but we're just not there yet.
Toole alludes to a software tool Harman has developed... hopefully it will become available for a reasonable price.
dave
Are there two camps on this?
One appears to be saying that owing to the peculiarities of bass management, I'd rather build a TMM, MTM, or other larger multi way and not introduce the physical/technical entanglements of separate subs.
Another seems to suggest that once I get the BSC, listening axis, wall boundaries, toe in, etc, perfected on my mains, then separate subwoofers, rather than posing entanglement, give me additional control over room modes and bass integration.
Is there disagreement there? Or have I misapprehended it?
One appears to be saying that owing to the peculiarities of bass management, I'd rather build a TMM, MTM, or other larger multi way and not introduce the physical/technical entanglements of separate subs.
Another seems to suggest that once I get the BSC, listening axis, wall boundaries, toe in, etc, perfected on my mains, then separate subwoofers, rather than posing entanglement, give me additional control over room modes and bass integration.
Is there disagreement there? Or have I misapprehended it?
There is only one camp: getting the bass right. A full range system basically places the subwoofers where the mains are. This is infrequently the optimal placement for low frequency sources. So with separate subwoofers the results won't be worse compared to a full range systems but you get the freedom of experimenting with different positions and settings (crossover, level, phase).
Best, Markus
Best, Markus
You'll probably will hear the argument that there is something like "stereo bass" which would require a low frequency extension of the mains (still the fact remains that additional low frequency source are needed to smooth the frequency response and extend it over more than just one listening position). Here's what Toole has to say:
"Most of the bass in common
program material is highly correlated or monophonic to begin with, and bassmanagement
systems are commonplace, but some have argued that it is
necessary to preserve at least two-channel playback down to some very low
frequency. It is alleged that this is necessary to deliver certain aspects of
spatial effect.
Experimental evidence thus far has not been encouraging to supporters of
this notion (Welti, 2004, and references therein). Audible differences appear to
be near or below the threshold of detection, even when experienced listeners are
exposed to isolated low-frequency sounds. The author has participated in a few
comparisons, carefully set up and supervised by proponents of stereo bass, but
each time the result has been inconclusive. With music and fi lm sound tracks,
differences in “spaciousness” were in the small to nonexistent category, but differences
in “bass” were sometimes obvious, as the interaction of the two woofers
and the room modes changed as they moved in and out of phase. These were
simple frequency-response matters that are rarely compensated for in such
evaluations. Even with contrived stereo signals, spatial differences were diffi cult
to tie down. This is not a mass-market concern. In fact, some of the discussion
revolved around the idea that one may need to undergo some training to hear
the effects.
Another recent investigation concludes that the audible effects benefi ting
from channel separation relate to frequencies above about 80 Hz (Martens et
al., 2004). In their conclusion, the authors identify a “cutoff-frequency boundary
between 50 Hz and 63 Hz,” these being the center frequencies of the octave
bands of noise used as signals. However, when the upper-frequency limits of the
bands are taken into account, the numbers change to about 71 Hz and 89 Hz,
the average of which is 80 Hz. This means, in essence, that it is a “stereo upperbass”
issue, and the surround channels (which typically operate down to 80 Hz)
are already “stereo” and placed at the sides for maximum benefi t. Enough
said."
"Most of the bass in common
program material is highly correlated or monophonic to begin with, and bassmanagement
systems are commonplace, but some have argued that it is
necessary to preserve at least two-channel playback down to some very low
frequency. It is alleged that this is necessary to deliver certain aspects of
spatial effect.
Experimental evidence thus far has not been encouraging to supporters of
this notion (Welti, 2004, and references therein). Audible differences appear to
be near or below the threshold of detection, even when experienced listeners are
exposed to isolated low-frequency sounds. The author has participated in a few
comparisons, carefully set up and supervised by proponents of stereo bass, but
each time the result has been inconclusive. With music and fi lm sound tracks,
differences in “spaciousness” were in the small to nonexistent category, but differences
in “bass” were sometimes obvious, as the interaction of the two woofers
and the room modes changed as they moved in and out of phase. These were
simple frequency-response matters that are rarely compensated for in such
evaluations. Even with contrived stereo signals, spatial differences were diffi cult
to tie down. This is not a mass-market concern. In fact, some of the discussion
revolved around the idea that one may need to undergo some training to hear
the effects.
Another recent investigation concludes that the audible effects benefi ting
from channel separation relate to frequencies above about 80 Hz (Martens et
al., 2004). In their conclusion, the authors identify a “cutoff-frequency boundary
between 50 Hz and 63 Hz,” these being the center frequencies of the octave
bands of noise used as signals. However, when the upper-frequency limits of the
bands are taken into account, the numbers change to about 71 Hz and 89 Hz,
the average of which is 80 Hz. This means, in essence, that it is a “stereo upperbass”
issue, and the surround channels (which typically operate down to 80 Hz)
are already “stereo” and placed at the sides for maximum benefi t. Enough
said."
Thank you. That was an interesting link. But 'stereo bass' actually isn't something I have come across much in the discussions of bass integration that I'm referring to. In fact, I'm planning on using two subwoofers. Whether I decide to send separate channels to each is something I'll read up on and experiment with later.
But it seems that I've read more and more often, in this forum and at least a few times on Zaphaudio and other builder's sites as well, "I prefer to listen to these without subwoofers" or statements to that affect. Not suggesting, so it seems, that there is any objection to the added cost, or clutter, or impossibility of achieving balance (these are pretty bright guys here with a lot of tools available to them) but that the subwoofer is actually detracting from some purity and adding something that simply cannot ever be well enough integrated into the performance to their satisfaction.
I'm also a bit concerned, now that I've had a chance to read more on this, that I should have looked further for subwoofer plate amps that had continuous 0-180 phase correction instead of the basic reversing switch that came with mine. That would have been pretty useful, no? What's the likelihood that I could just replace the switch with a pot? Nil?
But it seems that I've read more and more often, in this forum and at least a few times on Zaphaudio and other builder's sites as well, "I prefer to listen to these without subwoofers" or statements to that affect. Not suggesting, so it seems, that there is any objection to the added cost, or clutter, or impossibility of achieving balance (these are pretty bright guys here with a lot of tools available to them) but that the subwoofer is actually detracting from some purity and adding something that simply cannot ever be well enough integrated into the performance to their satisfaction.
I'm also a bit concerned, now that I've had a chance to read more on this, that I should have looked further for subwoofer plate amps that had continuous 0-180 phase correction instead of the basic reversing switch that came with mine. That would have been pretty useful, no? What's the likelihood that I could just replace the switch with a pot? Nil?
Last edited:
I think you'll find a heck of a lot of hifi loudspeaker manufacturers would disagree with that statement
I'm sure you have heard of the following so no point in linking to them. Wilson Audio (Maxx, Grand Slam, Sophia, System 8), ATC (50, 100, 200), Focal/JM lab (Grande Utopia etc, etc), etc, etc...These are all full range systems with a bass response down to the low 20Hz range or below 20Hz. Notice that there is no way of splitting the cabinets to move the bass speakers (System 8 excepted - they are designed to run one on top of the other though ).If i was you i'd forget about calling them "subwoofers" & simply call them (bass drivers) & full range loudspeakers once all is built into a single cabinet
Design the speakers so they aren't likely to add multiple room resonances in the bass frequencies. IE don't fire a port out the back & near the floor if it'll be close to a side or rear wall. Keep the bass driver away from the floor & possibly mount it on the enclosure side, this way you can keep it further from a side wall etc.
Yes i'm sure you could possibly get a bit better integration into a room by seperating the lower bass from the rest of the cabinet. However you'll need a damn sight more measuring equipment & setting up time probably as well as some equipment to do various things to time align drivers & sort levels out that can easily be calculated & taken into account when you know exactly where the bass driver voicecoil is in comparison to the midrange lets say.
Most people don't like large speakers simply because the wife doesn't
Therefore these people (unless they are rich & can get away to another dedicated room) tend to have spouse acceptable speakers & then sneak in a sub because the little ones can't do deep bass. Then the sub is often a compromise as well due to the aforementioned Nothing wrong with "FULL" range speakers in one lump, once they are positioned correctly in the room they are less messing about imo. I'm sure there are plenty of satisfied customers of the above
Bests, Mark.
Yes, nil & unfortunately very useful as regards getting the phase correct when placing "bass speakers" at a distance from main speakers.
If you have a pretty bad room and/or can't set up subwoofers correctly then having no bass is better than having bad bass.
That would be helpful but using a plain mono amp in combination with something like a Behringer DCX2496 will give you the freedom you need.
I think you'll find a heck of a lot of hifi loudspeaker manufacturers would disagree with that statement
I really couldn't care less because the anechoic data they present (if they present any usable data at all) is meaningless when you place a loudspeaker in a room. The room completely dominates low frequencies in acoustically small spaces. Anybody denying this wants the earth to be flat again - for whatever reason.
I agree, i don't see that many subwoofers costing over £20,000 / $33,000 or Euro 22,000 though & yet there appears to be no call for the manufacturers to split the enclosures.
Yes i can see where you are coming from
Just don't take it as an afront that i point out quality gear that doesn't conform to the seperate sub mentality. Any speaker is going to need careful positioning in any room & unless you are going to employ some kind of fancy software & a microphone i'd suggest it'd be a lot easier knowing how far driver voicecoils are from each other if you are going to set something up to get delay out the window (something like the DCX2496).If you don't have a DCX2496 then you'll need to be clever with opamps & all pass filters. Been there & done that - next speakers will use a 2496 which you seem to like
Chill... Different strokes for different folks, why do you assume i think the earth is flat when i'm an amateur astronomer
No harm done but please define quality when talking about the companies you just mentioned! The only quality I see is the ability to squeeze a lot of money out of their customers. The way they design speakers is not reasonable because they ignore one of the most important pieces in the reproduction chain: the room. Do they offer any solutions to address this? I don't see any. Look what Genelec or JBL is doing for the professional market. That's where the action is.
By the way, I don't like the DCX at all. It is buggy (digital input stage and the "frying egg" issue - http://www.dcx2496.fr/img/cs8420bug.png) and not built for our type of application. It's just the lesser evil.
The ATC 100 & 200 that i mentioned previously are often used for monitoring purposes in studios, i'm sure i can find some nice pics of the 200 which sports twin 15" bass drivers in a studio.
Please don't forget about treating a room, i'm sure they had to do it in the studio where they were making master recordings
Or perhaps they were or are "flat earth" believers as well.
E2A:- As for quality the ATC 75mm midrange is regarded as one of the best on the planet, i'm sure they used some kind of highly regarded tweeter to. Something from Vifa springs to mind. There isn't much doubt that ATC's bass units are very good either.
I prefer the Yamaha NS1000 midrange & tweeter above the ATC stuff though. No breakup in the audio band (when crossed over correctly for the mid) & 27KHz for the first breakup mode on the tweeter.
Please don't forget about treating a room, i'm sure they had to do it in the studio where they were making master recordings
Or perhaps they were or are "flat earth" believers as well.
E2A:- As for quality the ATC 75mm midrange is regarded as one of the best on the planet, i'm sure they used some kind of highly regarded tweeter to. Something from Vifa springs to mind. There isn't much doubt that ATC's bass units are very good either.
I prefer the Yamaha NS1000 midrange & tweeter above the ATC stuff though. No breakup in the audio band (when crossed over correctly for the mid) & 27KHz for the first breakup mode on the tweeter.
Last edited:
I believe that those calls are because there are a lot of crap drivers (and badly designed subwoofer boxes) sold/made specifically for the thump-thump parts of movies.
On top of that add in that subs have been commonly used singly which can really aggravaye room modes, and you end up with a situation wher eno bass is better than what you have.
dave
Planet10, what's your opinion of a LFE subwoofer located in a corner, that is 8 feet tall, with 2 x 10" woofers, 1 at the very bottom and 1 at the very top (both facing forward, divided enclosures). Would the vertical separation of the drivers significantly help to smooth the in-room response?
I'm attracted to this configuration from a space-efficiency perspective.
I'm attracted to this configuration from a space-efficiency perspective.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.