I searched for a thread on this and did not find one that was up to date and comprehensive regarding this most common setup. I'm guessing that 90 percent of "bass management" questions and answers apply to TM/sub setups on this forum.
The majority of subwoofers utilized in homes are likely just plugged and played. That sufficed for most of us until the last decade or so. The attention to bass management or integration (in the home) gets progressively more painstaking as the DIY bug lures you into the couple of dozen internet rabbit holes regarding the subject.
But I've been unable to find one really good thread applied to this. In fact, Brian Steele, of the diysubwoofer site, mentions recently ...
The Subwoofer DIY Page - Subwoofer Integration
While this page is informative, it actually does more to point out the bewildering range of approaches to this topic. Everyone (almost) suggests sealed, or ports defeated (stuffed), for optimum midrange accuracy... but without ever really explaining why this is accepted practice.
There is considerable support for the use of active crossovers (for the many of us that still use 2 chan, non HT, gear) in order to high pass the MT 'mains'. Again, the applications are frustratingly anecdotal and diffuse, with pro audio solutions seeming to be the norm. Another designer, whose knowledge I regard highly, suggests that if crossed over (high passed), the mains are better left ported.
In another thread here I pointed out that one highly regarded speaker builder suggested that a sealed 6 or 7 inch TM with sub could never really be expected to match the reference levels capable of a good TMM or MTM design.
http://www.audioheuristics.org/projects_gallery/Usher_satellites/usher_index.htm
And I seem to be noticing a small but growing trend of people kind of throwing up their hands in the face of all of this and simply foregoing these issues by building larger multi-ways.
I suspect that space and placement flexibility considerations (SAF) are often made in choosing smaller mains with subwoofers that can either be hidden or tucked somewhat out of sight. Does this really introduce such a can of worms for the average diy'er that he would well advised to opt for the TMM or MTM (or other such) in most cases?
Is it possible to get some consensus here in one thread on this subject?
The majority of subwoofers utilized in homes are likely just plugged and played. That sufficed for most of us until the last decade or so. The attention to bass management or integration (in the home) gets progressively more painstaking as the DIY bug lures you into the couple of dozen internet rabbit holes regarding the subject.
But I've been unable to find one really good thread applied to this. In fact, Brian Steele, of the diysubwoofer site, mentions recently ...
The link is here...
The Subwoofer DIY Page - Subwoofer Integration
While this page is informative, it actually does more to point out the bewildering range of approaches to this topic. Everyone (almost) suggests sealed, or ports defeated (stuffed), for optimum midrange accuracy... but without ever really explaining why this is accepted practice.
There is considerable support for the use of active crossovers (for the many of us that still use 2 chan, non HT, gear) in order to high pass the MT 'mains'. Again, the applications are frustratingly anecdotal and diffuse, with pro audio solutions seeming to be the norm. Another designer, whose knowledge I regard highly, suggests that if crossed over (high passed), the mains are better left ported.
In another thread here I pointed out that one highly regarded speaker builder suggested that a sealed 6 or 7 inch TM with sub could never really be expected to match the reference levels capable of a good TMM or MTM design.
(near the bottom of this page)
http://www.audioheuristics.org/projects_gallery/Usher_satellites/usher_index.htm
And I seem to be noticing a small but growing trend of people kind of throwing up their hands in the face of all of this and simply foregoing these issues by building larger multi-ways.
...just one of many such comments I've started to notice.
I suspect that space and placement flexibility considerations (SAF) are often made in choosing smaller mains with subwoofers that can either be hidden or tucked somewhat out of sight. Does this really introduce such a can of worms for the average diy'er that he would well advised to opt for the TMM or MTM (or other such) in most cases?
Is it possible to get some consensus here in one thread on this subject?
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Timely post Peacebrainerd. I'm thinking about putting together a webpage to summarise all my thoughts on this matter as I too have noticed a lack of clear advice. My new speaker project (Apollo) on another thread follows the principles I mention below.
Basically here's what I think (which admittedly is more of a purist approach):
Most users have little knowledge of crossover design, the physics of sound or room acoustics. The standards and approaches used by equipment manufactures vary widely in regard to crossover frequencies, levels, overload margins, how bass is routed between small/large/subwoofer speakers, different DVD/blu-ray/SACD/DVD-A requirements, etc, etc. Its so complex, with so little information provided to the user, that it usually ends up being a guessing game.
By using full-range main speakers, and all channels set to "large", everything is greatly simplified.
No bass management is necessary, and the subwoofer(s) are used for Low Frequency Effects (LFE) only.
The main speakers should be sealed. The 2nd order rolloff of a sealed enclosure has much less group delay, is easier to EQ and integrates better with the typical room and subwoofer. Properly designed, it shouldnt require any highpass filter in a domestic situation (reasonable power levels).
Being full range, ideally they should be bi-amped, with an actively driven woofer, with EQ for optimising the low-frequency integration with the (unknown) room.
I also prefer sealed subwoofers for their lower group delay, better cone-control, and easier ability to be EQ'd to a flat response (eg by Linkwitz transform). 2 subwoofers is probably the best overall choice from a performance/practicality standpoint.
To summarize, the whole system needs to be simplified, and the best way to achieve that is to use bi-amped full-range main speakers, centre and surrounds big enough that they can be set to "large" (no bass management), 2 x dedicated LFE subwoofers, and sealed enclosures all around.
Basically here's what I think (which admittedly is more of a purist approach):
Most users have little knowledge of crossover design, the physics of sound or room acoustics. The standards and approaches used by equipment manufactures vary widely in regard to crossover frequencies, levels, overload margins, how bass is routed between small/large/subwoofer speakers, different DVD/blu-ray/SACD/DVD-A requirements, etc, etc. Its so complex, with so little information provided to the user, that it usually ends up being a guessing game.
By using full-range main speakers, and all channels set to "large", everything is greatly simplified.
No bass management is necessary, and the subwoofer(s) are used for Low Frequency Effects (LFE) only.
The main speakers should be sealed. The 2nd order rolloff of a sealed enclosure has much less group delay, is easier to EQ and integrates better with the typical room and subwoofer. Properly designed, it shouldnt require any highpass filter in a domestic situation (reasonable power levels).
Being full range, ideally they should be bi-amped, with an actively driven woofer, with EQ for optimising the low-frequency integration with the (unknown) room.
I also prefer sealed subwoofers for their lower group delay, better cone-control, and easier ability to be EQ'd to a flat response (eg by Linkwitz transform). 2 subwoofers is probably the best overall choice from a performance/practicality standpoint.
To summarize, the whole system needs to be simplified, and the best way to achieve that is to use bi-amped full-range main speakers, centre and surrounds big enough that they can be set to "large" (no bass management), 2 x dedicated LFE subwoofers, and sealed enclosures all around.
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Oh how i agree with you except on one single point
If you tell any DVD or Blu Ray player that it doesn't have a subwoofer in the setup it'll force the LFE channel to both left & right front speakers. As long as you make them "full range" then no subwoofer is needed at all Obviously i mean make the stereo pair of speakers capable of 20Hz reproduction (full range) Gotta love sealed boxes for precisely the reasons you mention! Fast, accurate & low group delay. As well as that Linkwitz transform that puts the icing on the cake
You just need to move some air...
Oh how i agree with you except on one single point
Some do, dome don't (eg my Oppo), and some send a signal reduced 6dB.
See what I mean, it's a dog's breakfast.
But set your mains to large, AND use a subwoofer (for LFE only), and you should be fine no matter what.
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Ah, my apologies as i did query this elsewhere as i was wondering about it. I did get answers but now i'm wondering about there validitySome do, dome don't (eg my Oppo), and some send a signal reduced 6dB.
See what I mean, it's a dog's breakfast.
But set your mains to large, AND use a subwoofer (for LFE only), and you should be fine no matter what.
Yeah, i see it can be a total minefield. Looks like i'll need to find out what my film players do, ta for making me take more notice!
I hope we can get some input here as well from the minimalists. I rather prefer using 2chan integrated amplifiers. I don't have sub output, multi channels, or options for different speaker settings. I started the thread after agonizing over starting a TM with subwoofer project and bumping into so many of the integration issues. I"m dedicated, for now, to using 2chan integrateds, and just took delivery on a couple of sub plate amps from the NHT sale.
Two questions to start off. Why can't the mains be crossed high at chosen point, say 80hz, with a simple discrete circuit and left at that?
Again, there's no one source or thread that addresses the pros and cons of FMOD preamp outputs vs an 80 dollar Behringer active crossover vs (ideally) designing the main speakers internal crossover to filter sub 80hz (is this possible? or does it introduce too many trade offs in terms of cost, insertion loss, etc?)
Two questions to start off. Why can't the mains be crossed high at chosen point, say 80hz, with a simple discrete circuit and left at that?
Again, there's no one source or thread that addresses the pros and cons of FMOD preamp outputs vs an 80 dollar Behringer active crossover vs (ideally) designing the main speakers internal crossover to filter sub 80hz (is this possible? or does it introduce too many trade offs in terms of cost, insertion loss, etc?)
Except that to get good unpeaky bass response in a room, sitting underneath the mains is not anywhere near an ideal placement for the LF drivers.
dave
Basically, what you've doing is designing a bi-amped full-range speaker, which, as I said, is the best solution. And you have the added benefit of being able to locate the subs anywhere ( nod to Planet10 above
)If you must rolloff the bottom of the mains, you could us a simple line-level capacitor between pre and power amps (6dB/octave) or something like the FMOD (12db/octave). Does your integrated amp have pre-outs and main-in connections? If your sub amp has 24dB/octave lowpass, then use that with the FMOD on the mains which will give you a 4th order Linkwitz-Riley crossover at 80Hz-100Hz.
Quite a neat solution, but with 2 compromises - a poorer group delay (than a shallower-sloped crossover), and you're missing out on the LFE channel (but you could add another sub later).
A Behringer crossover could be used, but being active and more complex it will have some negative effects on sound quality.
A passive highpass filter at 80Hz could be done but would be very expensive and lossy (eg 500uF capacitor, 10mH inductor), and wouldnt function well as it would be operating around the woofer's resonance (where the impedance varies widely). I wouldnt recommend it.
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What are the pros and cons of these two components...
Parts-Express.com:*Behringer CX2310 Super-X Pro Crossover 2-Way/3-Way | Crossovers crossover 3-way crossover 2-way crossover active crossover
Creative Sound - Product Details
...and are they really the most straightforward solution to bass integration? I'm actually not as demanding regarding this as this thread might suggest. I'd merely like to rest somewhat assured that I've addressed the grossest errors that might result from no attempt at integration at all.
Heck, why not even this one...
http://www.creativesound.ca/details.php?model=F-1
...?
Parts-Express.com:*Behringer CX2310 Super-X Pro Crossover 2-Way/3-Way | Crossovers crossover 3-way crossover 2-way crossover active crossover
Creative Sound - Product Details
...and are they really the most straightforward solution to bass integration? I'm actually not as demanding regarding this as this thread might suggest. I'd merely like to rest somewhat assured that I've addressed the grossest errors that might result from no attempt at integration at all.
Heck, why not even this one...
http://www.creativesound.ca/details.php?model=F-1
...?
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I'm a bit suprised that there is not more interest in this thread. I might have posted it in the subwoofer section, but wanted to get the question out in front of others at diyaudio who might be reasonably dissatisfied in subwoofers, resulting from the integration problems, and able to state why they don't go there.
So with all of the associated pros/cons of the aforementioned solutions, which provides the best balance of low complexity and reward?
So with all of the associated pros/cons of the aforementioned solutions, which provides the best balance of low complexity and reward?
I suspect that this is going to drive me a bit nutty before the end. I located this thread, read the opening post and, noticing that it went on for some pages, thought "A-hoy! The holy grail!!!"
http://www.diyaudio.com/forums/subwoofers/116274-simple-subwoofer-crossover.html
And then proceded down another rabbit hole into a discussion referencing kits, op-amps, linkwitz, and some terminology that had me darting back to google to get my bearings. And this following a pretty off putting remark half way through the thread should you choose to ignore all of this complexity, to wit..
I'll have to back up a bit and own my near complete ignorance here.
Begin with the most 'common' approach to building a three way speaker with passive crossovers. The mid range driver picks up at a chosen point above the woofer. Accomplished with passive components. Some speakers are designed with 'built in' subwoofers and attached plate amps. In these, the mid driver is asked to provide more of the lower freq. Is this why it's costly/lossy to incorporated a passive crossover? As far as I've seen, they don't typically incorporate additional active crossover electronics. How are these high passed to the TM section?
Just what is it about physically separating the sub from the mains that gives rise to all these complexities? The option to place the subwoofer where you wish is mentioned as a plus earlier in this thread. But is it worth the "time/phase/amplitude" headaches? I think I'm missing the big picture somehow. It's a problem that is, quite evidently, applicable to huge numbers of subwoofer owners, that appears to be beyond the scope of 98 percent of them to remedy.
So, honestly here folks, if the only way for the average diyer to negotiate a labyrinth of "time/phase/amplitude physics and complex filters and DSP" with any success, on his own, at least in the near term, is to toss aside the plans for his subwoofer and build a full range design then is that the state we're in?
http://www.diyaudio.com/forums/subwoofers/116274-simple-subwoofer-crossover.html
And then proceded down another rabbit hole into a discussion referencing kits, op-amps, linkwitz, and some terminology that had me darting back to google to get my bearings. And this following a pretty off putting remark half way through the thread should you choose to ignore all of this complexity, to wit..
C'mon. Is babble really going to ruin the fun of this hobby for such simpletons as myself?
I'll have to back up a bit and own my near complete ignorance here.
Begin with the most 'common' approach to building a three way speaker with passive crossovers. The mid range driver picks up at a chosen point above the woofer. Accomplished with passive components. Some speakers are designed with 'built in' subwoofers and attached plate amps. In these, the mid driver is asked to provide more of the lower freq. Is this why it's costly/lossy to incorporated a passive crossover? As far as I've seen, they don't typically incorporate additional active crossover electronics. How are these high passed to the TM section?
Just what is it about physically separating the sub from the mains that gives rise to all these complexities? The option to place the subwoofer where you wish is mentioned as a plus earlier in this thread. But is it worth the "time/phase/amplitude" headaches? I think I'm missing the big picture somehow. It's a problem that is, quite evidently, applicable to huge numbers of subwoofer owners, that appears to be beyond the scope of 98 percent of them to remedy.
So, honestly here folks, if the only way for the average diyer to negotiate a labyrinth of "time/phase/amplitude physics and complex filters and DSP" with any success, on his own, at least in the near term, is to toss aside the plans for his subwoofer and build a full range design then is that the state we're in?
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Well, there's not much (or too much) to say because the answer is "it depends". It depends heavily on your room and the number of low frequency sound sources. In some rooms (like mine) you might get away with a single EQed sub. In others you need a lot of expensive absorption. If you want to have a smooth bass response across multiple seats then you need to have multiple subwoofers. In any case you need to do measurements. Each room is different.
These are the only simple solutions I can recommend but they work for a single listening position only:
a) Single subwoofer in the near field behind your head (< 1 ft)
b) Single subwoofer in a room corner + automated EQ (e.g. Anti-Mode 8033)
You should do measurements to get the crossover region to the mains right.
Best, Markus
These are the only simple solutions I can recommend but they work for a single listening position only:
a) Single subwoofer in the near field behind your head (< 1 ft)
b) Single subwoofer in a room corner + automated EQ (e.g. Anti-Mode 8033)
You should do measurements to get the crossover region to the mains right.
Best, Markus
Hi
First I have to admit I'm no purist and want the biggest bang for buck I can.
I use the Behringer CX2310 and I am really happy with the performance fr the dollar, they are not the best quality, are sometimes a little noisy and break down occasionally, but do make the entry into Bi-Amping easy, and the interconnects also make using multiple subs an option.
Keep the XO frequency blow 120 Hertz and feel the difference it can make, if your main speakers are already a 3-way cut them at 80Hertz or lower and see if the mid-range becomes a little clearer ( sometimes it can if the XO is first order and a little low ) as all the low bass is then handled by the subs
First I have to admit I'm no purist and want the biggest bang for buck I can.
I use the Behringer CX2310 and I am really happy with the performance fr the dollar, they are not the best quality, are sometimes a little noisy and break down occasionally, but do make the entry into Bi-Amping easy, and the interconnects also make using multiple subs an option.
Keep the XO frequency blow 120 Hertz and feel the difference it can make, if your main speakers are already a 3-way cut them at 80Hertz or lower and see if the mid-range becomes a little clearer ( sometimes it can if the XO is first order and a little low ) as all the low bass is then handled by the subs
A pic may help clarify things. Here's the basic configuration of my current Apollo project.
I havent yet decided on what product I'll use for the active lowpass/EQ section.
I've also knocked together a page showing the how subwoofers and main speakers integrate using a variety of crossovers.
Bass Management
I havent yet decided on what product I'll use for the active lowpass/EQ section.
An externally hosted image should be here but it was not working when we last tested it.
I've also knocked together a page showing the how subwoofers and main speakers integrate using a variety of crossovers.
Bass Management
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