Hi All,
I wonder if I could get a bit of input from people on trying to choose a model of subwoofer that would be suitable for use in a Geddes style multi-sub system where the primary purpose of the subwoofers is modal smoothing in the room for music playback rather than the typical home theatre "one giant sub to shake your house" approach that many subwoofers seem to be designed for.
Those who've read my posts before know I love ground up speaker design and currently have a new 3 way design in progress, (although semi on-hold due to circumstances outside my control) however for whatever reason I have zero interest in designing and building my own powered subwoofer, let alone the time to do it when I can't even find time to progress my 3 way design.
The main speakers which will (one day) be my main system are going to be a large floor standing 110(ish) litre bass reflex 3 way system - 12" woofer, 8" full range driver for midrange and ribbon tweeter.
In terms of bass response these will be tuned to around 25Hz and will have an early gradual roll-off alignment that will give a response that is about 6dB down at 25Hz before room gain is factored in, in short these should be good down to at least 25Hz in-room probably a bit lower and at a reasonably high SPL, as the ports will provide significant loading and gain vs sealed from around 20-40Hz.
So I won't need subwoofers to supplement the low end response of these speakers nor maximum SPL, however I will benefit from subwoofers to help with modal smoothing, as there are significant standing wave/boundary cancellation issues in this room that I can't do anything about passively, and speaker/listener positioning is extremely constrained by the size of the room and other stuff in the room.
It's a small British living room with a bay window on one end and the main sofa directly against the back wall. The front to back wall is 4.3 metres (hence the 40Hz fundamental mode) sideways its 3.8 metres, but 4.5 metres if you include the bay window in the left hand wall from the listener perspective. On the right hand wall is a 2 seat sofa and in the bay window there is a chair.
To its benefit we have high 2.8 metre ceilings, which does seem to help a bit with acoustics at higher frequencies and increases the room volume significantly for the small footprint.
The internal and external walls are all solid brick and plaster so not good for standing waves however the floor is a beam suspended wooden floor (with nearly a metre of crawl space and then dirt below) with carpet and the ceiling is gyprock / plasterboard suspended from wooden beams with some loft space above it and a second suspended wooden floor over parts of it as well.
So while the walls are bad for standing waves the floor and ceiling are probably quite good. Standing waves are still an issue but not as bad as a previous house I lived in with brick walls and carpet over a concrete floor which was really problematic...
The 2 way speakers I have at the moment only go down to around 40Hz and unlike the eventual 3 way design to replace them have the woofers high off the floor, which tends to exacerbate boundary cancellation issues.
The main issues I have are:
1) Large peak at 41Hz on the order of around 10dB at the listening position that has to be pulled way down with a PEQ, which then causes a hole at that frequency in other locations in the room. To fix this I probably need at least one subwoofer on the back (listener) wall to cancel the fundamental mode since a woofer in phase at the back wall would reduce the response at the back wall by the listener but increase it in the middle and most other locations in the room.
2) About a 6dB peak at 71Hz which I likewise pull down with a PEQ. I presume this is something to do with the ceiling reflection but I haven't really tried to work it out.
3) A big hole around 80-90Hz - almost complete cancellation at the listening position, and this is one of the things I'd really like to address with a multi-sub configuration as I can't do anything about it with EQ.
4) A nasty peak at around 105Hz which makes bass sound congested if I don't correct it with EQ.
5) A large depression right from 120Hz to 180Hz or so presumably due to boundary cancellation from the wall/corner behind the speakers, and I assume this would only be correctable by a subwoofer relatively close to the main speakers (due to the high frequency) such as the front right corner of the room about a metre from the main right speaker.
This depression can cause a lack of warmth on some material especially if I fully correct the nearby peak because there is not much energy between 100-200Hz once that 105Hz peak is corrected. (As a result I only partially correct the 105Hz peak until it doesn't sound congested to avoid losing all warmth in the upper bass) I would really like to do something about this depression in the 100-200Hz range.
Interestingly because the bay window makes the room asymmetrical no matter where you put the speakers, (in this room orientation) there is a big difference in the boundary cancellation of the left and right speakers. This was measured at the sofa at ear height with no gating so ignore anything above 200Hz:
As can be seen the left speaker (red) suffers considerably more severe cancellation (including 55Hz, 130Hz etc) than the right speaker or the summed response. This can sound a bit weird when a note at 130Hz is coming primarily from the right speaker for instance.
There are only really 3 places subwoofers could fit and work in with the furnishings.
One is to the left of the sofa where there is a 50cm gap to the wall which currently has a 45cm high table for a lamp, pot plant, remote controls etc, so a subwoofer of around 45x45x45 cm would fit there if it had a flat, wood grain top which could double as a table. (Egg shaped subwoofers need not apply)
The second possible location is in the far right corner near the right speaker, where there is a fair bit of room now that a toy chest is gone. It might have to have a pot plant standing on it as well...
The third possible location is to the right of the speaker part way up the right wall beside the side sofa. This one could be no bigger than about 40cm x 40cm x 40cm to fit under a small table that is there and clear the door.
So, what models to consider ? I'm not looking for a large sub home theatre style, several smaller subs with the same combined output of one large sub are much more suited to the multi-sub approach.
While I only want to buy one for now so I can make a useful improvement to the cancellation / bass issues I'm having with the current 2 way system and use it as a testing tool to measure the performance of different locations in the room, it needs to be cheap enough that I can afford eventually increasing the number of subs to 3, both for use with the current 2 way system and ultimately with the new 3 way system.
Features I'm looking for - discrete box shaped sub with a flat top surface that is either black or wood grained suitable for putting a plant on top of etc, and preferably with either a cover over the woofer or down facing woofer to make it look discrete. There needs be at least one side that doesn't have any controls and is either blank or has a cover over the woofer for aesthetics and also protection from an inquisitive 5 year old.
Adjustable low pass frequency, level, phase and auto-sensing power on. More advanced EQ would be nice but I doubt anything in my budget range would have that.
I already have a DEQ2496 on the system for overall EQ so after sub level matching, low pass filter settings, phase etc are all optimised as much as possible I can "clean up" the remaining bass balance with the DEQ2496.
I know pretty much nothing about what's out there in commercial subs and most of the reviews I've looked at are written for lay people by people that don't have any technical knowledge of speakers themselves so I'm hoping that I can get a few pointers of where to start looking...
I wonder if I could get a bit of input from people on trying to choose a model of subwoofer that would be suitable for use in a Geddes style multi-sub system where the primary purpose of the subwoofers is modal smoothing in the room for music playback rather than the typical home theatre "one giant sub to shake your house" approach that many subwoofers seem to be designed for.
Those who've read my posts before know I love ground up speaker design and currently have a new 3 way design in progress, (although semi on-hold due to circumstances outside my control) however for whatever reason I have zero interest in designing and building my own powered subwoofer, let alone the time to do it when I can't even find time to progress my 3 way design.
The main speakers which will (one day) be my main system are going to be a large floor standing 110(ish) litre bass reflex 3 way system - 12" woofer, 8" full range driver for midrange and ribbon tweeter.
In terms of bass response these will be tuned to around 25Hz and will have an early gradual roll-off alignment that will give a response that is about 6dB down at 25Hz before room gain is factored in, in short these should be good down to at least 25Hz in-room probably a bit lower and at a reasonably high SPL, as the ports will provide significant loading and gain vs sealed from around 20-40Hz.
So I won't need subwoofers to supplement the low end response of these speakers nor maximum SPL, however I will benefit from subwoofers to help with modal smoothing, as there are significant standing wave/boundary cancellation issues in this room that I can't do anything about passively, and speaker/listener positioning is extremely constrained by the size of the room and other stuff in the room.
It's a small British living room with a bay window on one end and the main sofa directly against the back wall. The front to back wall is 4.3 metres (hence the 40Hz fundamental mode) sideways its 3.8 metres, but 4.5 metres if you include the bay window in the left hand wall from the listener perspective. On the right hand wall is a 2 seat sofa and in the bay window there is a chair.
To its benefit we have high 2.8 metre ceilings, which does seem to help a bit with acoustics at higher frequencies and increases the room volume significantly for the small footprint.
The internal and external walls are all solid brick and plaster so not good for standing waves however the floor is a beam suspended wooden floor (with nearly a metre of crawl space and then dirt below) with carpet and the ceiling is gyprock / plasterboard suspended from wooden beams with some loft space above it and a second suspended wooden floor over parts of it as well.
So while the walls are bad for standing waves the floor and ceiling are probably quite good. Standing waves are still an issue but not as bad as a previous house I lived in with brick walls and carpet over a concrete floor which was really problematic...
The 2 way speakers I have at the moment only go down to around 40Hz and unlike the eventual 3 way design to replace them have the woofers high off the floor, which tends to exacerbate boundary cancellation issues.
The main issues I have are:
1) Large peak at 41Hz on the order of around 10dB at the listening position that has to be pulled way down with a PEQ, which then causes a hole at that frequency in other locations in the room. To fix this I probably need at least one subwoofer on the back (listener) wall to cancel the fundamental mode since a woofer in phase at the back wall would reduce the response at the back wall by the listener but increase it in the middle and most other locations in the room.
2) About a 6dB peak at 71Hz which I likewise pull down with a PEQ. I presume this is something to do with the ceiling reflection but I haven't really tried to work it out.
3) A big hole around 80-90Hz - almost complete cancellation at the listening position, and this is one of the things I'd really like to address with a multi-sub configuration as I can't do anything about it with EQ.
4) A nasty peak at around 105Hz which makes bass sound congested if I don't correct it with EQ.
5) A large depression right from 120Hz to 180Hz or so presumably due to boundary cancellation from the wall/corner behind the speakers, and I assume this would only be correctable by a subwoofer relatively close to the main speakers (due to the high frequency) such as the front right corner of the room about a metre from the main right speaker.
This depression can cause a lack of warmth on some material especially if I fully correct the nearby peak because there is not much energy between 100-200Hz once that 105Hz peak is corrected. (As a result I only partially correct the 105Hz peak until it doesn't sound congested to avoid losing all warmth in the upper bass) I would really like to do something about this depression in the 100-200Hz range.
Interestingly because the bay window makes the room asymmetrical no matter where you put the speakers, (in this room orientation) there is a big difference in the boundary cancellation of the left and right speakers. This was measured at the sofa at ear height with no gating so ignore anything above 200Hz:
As can be seen the left speaker (red) suffers considerably more severe cancellation (including 55Hz, 130Hz etc) than the right speaker or the summed response. This can sound a bit weird when a note at 130Hz is coming primarily from the right speaker for instance.
There are only really 3 places subwoofers could fit and work in with the furnishings.
One is to the left of the sofa where there is a 50cm gap to the wall which currently has a 45cm high table for a lamp, pot plant, remote controls etc, so a subwoofer of around 45x45x45 cm would fit there if it had a flat, wood grain top which could double as a table. (Egg shaped subwoofers need not apply)
The second possible location is in the far right corner near the right speaker, where there is a fair bit of room now that a toy chest is gone. It might have to have a pot plant standing on it as well...
The third possible location is to the right of the speaker part way up the right wall beside the side sofa. This one could be no bigger than about 40cm x 40cm x 40cm to fit under a small table that is there and clear the door.
So, what models to consider ? I'm not looking for a large sub home theatre style, several smaller subs with the same combined output of one large sub are much more suited to the multi-sub approach.
While I only want to buy one for now so I can make a useful improvement to the cancellation / bass issues I'm having with the current 2 way system and use it as a testing tool to measure the performance of different locations in the room, it needs to be cheap enough that I can afford eventually increasing the number of subs to 3, both for use with the current 2 way system and ultimately with the new 3 way system.
Features I'm looking for - discrete box shaped sub with a flat top surface that is either black or wood grained suitable for putting a plant on top of etc, and preferably with either a cover over the woofer or down facing woofer to make it look discrete. There needs be at least one side that doesn't have any controls and is either blank or has a cover over the woofer for aesthetics and also protection from an inquisitive 5 year old.
Adjustable low pass frequency, level, phase and auto-sensing power on. More advanced EQ would be nice but I doubt anything in my budget range would have that.
I already have a DEQ2496 on the system for overall EQ so after sub level matching, low pass filter settings, phase etc are all optimised as much as possible I can "clean up" the remaining bass balance with the DEQ2496.
I know pretty much nothing about what's out there in commercial subs and most of the reviews I've looked at are written for lay people by people that don't have any technical knowledge of speakers themselves so I'm hoping that I can get a few pointers of where to start looking...
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I would start by looking at BK subs. The XL200 is based on Peerless XLS10 driver and I would think would make a good balancing sub. They do a good range of finishes and if you call them direct they will offer sound advice and can make bespoke changes for you.
The Uk price of a decent sealed 12 sub is creeping up to £1k at the moment so not sure what budget you had in mind.
The Uk price of a decent sealed 12 sub is creeping up to £1k at the moment so not sure what budget you had in mind.
A Dayton Audio RSS265HF-8 is probally your best bet on a budget, works without eq to F6 of 25 in a 45L sealed cabinet and has enough excursion and power to work as a solo sub also. The size of that cabinet is could be 40x40x40cm in 21mm plywood (probally best for such a sub). Add some bracing, and fill it with stuffing to get back the volume and damping and it fits your need i think.
If you got (a lot) more budget, a Scan-Speak 23W/4557T00 or 23W/4557T02 or a Seas L26ROY could probally do the job also. But i doubt it will be that better for this function.
If you got (a lot) more budget, a Scan-Speak 23W/4557T00 or 23W/4557T02 or a Seas L26ROY could probally do the job also. But i doubt it will be that better for this function.
Thanks for the suggestion to check out BK, thebizz.
Looking through the BK line, as well as being UK based (easier to buy post-Brexit...) they have a reasonable selection with varying spec levels and finishes, this one caught my eye already and in light oak has WAF:
XLS200-DF
£355 is a pretty decent price. While it's one of their lower end models, the whole point of a multi-sub system is to have multiple sources of bass in the room rather than one high power sub in one location.
To achieve that good modal smoothing you really need 2-3 widely dispersed subs so three large subs that were individually powerful enough on their own would be overkill and not as good bang for your buck as using multiple smaller subs.
I also quite like the idea of a downwards facing sub - not only does it give it terrific child protection and make it look like a piece of furniture instead of a speaker, the floor does provide loading that helps improve the performance.
Years ago when I had what was basically a passive sub I always found that facing it backwards into the corner of the room (with a suitable gap) gave better boundary cancellation removal than facing it forwards, so there are benefits to having the cone close to a boundary.
I'll keep looking around but will definitely bookmark this one as a possibility.
For £50 more they also have this model:
Platinum P12300-SB
Looking through the BK line, as well as being UK based (easier to buy post-Brexit...) they have a reasonable selection with varying spec levels and finishes, this one caught my eye already and in light oak has WAF:
XLS200-DF
£355 is a pretty decent price. While it's one of their lower end models, the whole point of a multi-sub system is to have multiple sources of bass in the room rather than one high power sub in one location.
To achieve that good modal smoothing you really need 2-3 widely dispersed subs so three large subs that were individually powerful enough on their own would be overkill and not as good bang for your buck as using multiple smaller subs.
I also quite like the idea of a downwards facing sub - not only does it give it terrific child protection and make it look like a piece of furniture instead of a speaker, the floor does provide loading that helps improve the performance.
Years ago when I had what was basically a passive sub I always found that facing it backwards into the corner of the room (with a suitable gap) gave better boundary cancellation removal than facing it forwards, so there are benefits to having the cone close to a boundary.
I'll keep looking around but will definitely bookmark this one as a possibility.
For £50 more they also have this model:
Platinum P12300-SB
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I think Geddes promotes not using the same subwoofers in multi sub setups, so maybe just buy 3 random subs ?
I use 4 x eminence Lab12 drivers. I have 2 double 12 subs, one in the rear corner, one a few feet from the sofa (no space for a 3rd sub) Even 2 subs improves things.
Have you tried flipping polarity to lose the 80Hz dip ? (might be out of phase near xo region)
I have considered doing my multi sub setup using budget drivers, as they shouldn't need huge xmax if there are lots of them.
Exceptionally affordable stuff like these.
Cheers,
Rob.
I use 4 x eminence Lab12 drivers. I have 2 double 12 subs, one in the rear corner, one a few feet from the sofa (no space for a 3rd sub) Even 2 subs improves things.
Have you tried flipping polarity to lose the 80Hz dip ? (might be out of phase near xo region)
I have considered doing my multi sub setup using budget drivers, as they shouldn't need huge xmax if there are lots of them.
Exceptionally affordable stuff like these.
Cheers,
Rob.
I don't recall seeing that recommendation.
He does recommend semi-random placement (rather than a symmetrical layout) within certain guidelines, such as one near the listener, one on a side wall and one near one of the main speakers, and those three locations are feasible for me although the sidewall location would need to be the smaller model of the two I linked to fit in the available space. The other two locations would easily fit the 400x400x460mm model.
Flipping the polarity of what ? I don't have any subwoofers at the moment (hence the topic of this thread) and there are no crossovers near 80Hz.
It's boundary cancellation of some sort as the notch isn't there in the nearfield response.
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Hi Simon,
Yes that was my mistake. I'm so used to looking at response graphs that whenever I see a big dip around 80Hz I automatically think the subs are out of phase 😀
I'm quite positive I have read on this forum Geddes saying that different subs are better. Though over the years his recommendations have changed (used to promote 4th order bandpass as the best, now suggests sealed subs. Used to suggest plate amps, now suggest DSP and pro amps) A quick look at his papers has him suggesting one sub that goes deep in the corner behind the mains with multiple smaller subs to augment that sub. Maybe that's what I read before and interpreted as 'use different subs'
Cheers,
Rob.
Yes that was my mistake. I'm so used to looking at response graphs that whenever I see a big dip around 80Hz I automatically think the subs are out of phase 😀
I'm quite positive I have read on this forum Geddes saying that different subs are better. Though over the years his recommendations have changed (used to promote 4th order bandpass as the best, now suggests sealed subs. Used to suggest plate amps, now suggest DSP and pro amps) A quick look at his papers has him suggesting one sub that goes deep in the corner behind the mains with multiple smaller subs to augment that sub. Maybe that's what I read before and interpreted as 'use different subs'
Cheers,
Rob.
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+1 for heterogeneity... and in lots of places where wannabee engineers naively crave uniformity.
No impairment of localization on music with XO anywhere to 130 Hz, if drivers clean and XO slope steep.
Serious discussion is needed whether to go for mixed-bass or not.
B.
No impairment of localization on music with XO anywhere to 130 Hz, if drivers clean and XO slope steep.
Serious discussion is needed whether to go for mixed-bass or not.
B.
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No worries. 🙂
It's a few years since I've read the related threads, and maybe his opinions have shifted a bit over time but my interpretation of it with some of my own thinking rolled in is:
1) More discrete, spatially distributed sources of bass is better than less sources. (with diminishing returns, probably past around 3-4 subwoofers)
2) Symmetry of room and sources of bass is not a good thing, since symmetry causes boundary cancellation of pairs of speakers to fall on the same frequencies, effectively halving the number of discrete sources you have from a modal smoothing perspective.
You can see this in my room where some notches fall on the same frequencies for both left and right speakers where there is symmetry (probably front/back and floor/ceiling modes/boundary cancellation) but do not where there is not symmetry. (sideways modes/boundary cancellation) If the sideways dimension was symmetrical in my room as well I'd be in a much worse situation than I am at the moment.
3) To cancel the fundamental front/rear mode (41Hz in my room) you need as least one source of bass at the back of the room, which in my case is quite near the listener. This reduces the amplitude of the peak as heard at the rear of the room, (woofers at both ends of the room are out of phase with each other from the perspective of this location) while simultaneously increasing the amplitude at this frequency in the middle of the room where there was previously a hole. (Woofers are summing at this point) Having the subwoofer at the same end of the room as the speakers doesn't help smooth this lowest mode.
4) To fill in cancellation at frequencies from 100-200 you'd need a subwoofer near but not too close to one of the main speakers. Ideally about half a wavelength at ~150Hz from a main speaker towards a corner. A woofer near the listener would also fill in this range but might cause some localisation. (Although that's something I'll be experimenting with)
5) Deliberately using a non-symmetrical subwoofer layout means that you don't have to use identical subwoofers, since you're working more on the basis of statistical averaging of semi-randomly placed sources. Having the subwoofers themselves the same isn't harmful, just not necessary.
6) If the main speakers cross over to the subwoofers then you should only really be counting the subwoofers when deciding whether you have enough for modal smoothing, however if the main speakers fully or mostly overlap the subwoofers (which is kind of the point of the multi-sub approach where you want as many spatially separated sources of bass as possible at a given frequency) then technically they also count as subwoofers for modal smoothing.
For example my current main speakers go down to around 40Hz or about the same as the lowest room mode, while the subwoofers might be capable of going down to around 20-25Hz.
So in the 40-120Hz range the main speakers and subwoofers will be overlapping for maximum modal smoothing. Obviously this summing would result in too much bass overall but once I found the subwoofer configuration that gave the smoothest bass I would then use the DEQ2496 to pull down the bass level and finesse any remaining bumps to get a balanced overall result. (I have pretty much infinite adjustability available to dial in the desired bass response once the modes and boundary cancellation issues are mostly dealt with)
As always with bass, every room is different and plenty of experimentation and measurement/adjustment is required to find the optimal solution for a given number of woofers. 🙂
Another trick that can be used to predict the performance of a multi-sub system when I (initially) only have one available, is I can do a dual channel measurement in ARTA with the microphone at a given location, taking multiple measurements with the subwoofer in each of the (in my case) 3 feasible locations, those impulse responses can then be added in a phase coherent way to show exactly the result you'd get at that point in space if you did have all 3 subwoofers simultaneously in the room, or any combination thereof.
So a lot of testing and prediction of the response in that specific room can be done with a single subwoofer with the right measurement equipment which lets you do phase coherent virtual summing of the different measurements of subwoofer at different locations...
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My take on the situation is that with a statistically averaged modal smoothing technique like the Geddes multi-sub approach, subwoofers don't have to be the same to get good results but by the same token it doesn't hurt if they are the same. The key is the spatial separation of woofers that overlap in frequency.
This will be something I'll be testing - initially I would only have one subwoofer available and will have to decide between putting it in the rear left corner beside the sofa near the listener or the front right corner near a main speaker. Testing how localisable 130Hz is with it in the rear left corner is on my agenda as the rear location would give better smoothing of the 41Hz mode.
Some of the subwoofers I'm considering use down facing drivers - this provides a natural acoustic low pass filter in addition to the electrical low pass filter, and unlike the electrical filter this acoustic low pass filter also filters harmonics generated by the driver itself.
So in theory a subwoofer with a down facing woofer will have less high frequency leakage, and should be less localisable.
Not sure what you mean by "mixed-bass" ?
The ceiling is 2.8 metres high so the floor ceiling fundamental mode is about 61Hz, and while there is a bump at that frequency the worst peak in that region is 71Hz so seems to have a different cause, what I'm not exactly sure, as a diagonal bounce from the ceiling to the back of the room would be at a lower frequency not a higher frequency...
"Mixed bass" is where you sum L and R.
With speakers nearby the listener, they tattle their presence and spoil spatial localization.
There's no seriously low bass unless some sub(s) goes low. I do lots of real-time checks and - at least for music - large side-drums with stupendous bass might get down to 30 Hz. 32 Hz usual lowest. Occasional organ pedal recordings go as low as the hall ventilation equipment the mic picks up.
B.
With speakers nearby the listener, they tattle their presence and spoil spatial localization.
There's no seriously low bass unless some sub(s) goes low. I do lots of real-time checks and - at least for music - large side-drums with stupendous bass might get down to 30 Hz. 32 Hz usual lowest. Occasional organ pedal recordings go as low as the hall ventilation equipment the mic picks up.
B.
Ah ok, you're referring to mono bass feeds to all subwoofers.
Yes this is an interesting debate. I can see the argument for both sides.
If you did as part of a multi-sub system happen to have a sub in both front and right corner locations behind the main speakers and within a metre or two of them my inclination would be to drive those subwoofers from only left and right channels and not use a mono bass signal - that would allow you to take them right up to around 160Hz or so to help fill in that problematic 100-200Hz range without worrying about localisation.
At those frequencies the only localisation you have is a broad left/right sense, so as long as the front left subwoofer played the left channel bass and the front right one played the right channel bass it wouldn't upset localisation.
On the other hand if you have a highly asymetric subwoofer placement and/or some placed at the rear wall, those probably need to be driven with a mono (mixed) signal with a lower cut-off frequency to avoid localisation.
IMO it's a mistake to limit oneself to the lowest frequency that traditional acoustic instruments can produce.
I listen to plenty of music with electronic bass that goes way below 32Hz. I have headphones that go down to around 24Hz fairly flat and there are a lot of bass notes that are punchy and clearly audible at those very low frequencies which my current speakers utterly fail to reproduce as you don't hear much from them below 35Hz. (I don't even hear a noise at all - no doubling, just silence when that low note is playing causing that note to go missing)
Years ago in another country I had a system that went down below 25Hz easily and I really miss those lower frequencies - and music containing them is even more common now than it was 15 years ago when I had that system. Having headphones that can play that low is a constant reminder to me of what I'm missing with whole bass notes in phrases in a song going missing in action.
If your tastes start and end at acoustic instruments 32Hz is probably fine for you, but anyone who listens to electronic music will want to hear lower.
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Betcha there's some divergence between your impressions of low Hz and what an RTA might actually reveal.*
What a great surprise it would be to find you posting the RTA.
Just why would anybody produce recordings that nobody could play, Boston Audio Society excepted.
B.
*Canadians are so very polite.
What a great surprise it would be to find you posting the RTA.
Just why would anybody produce recordings that nobody could play, Boston Audio Society excepted.
B.
*Canadians are so very polite.
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Betcha there isn't. 😉
I know what certain bass frequencies sound like thanks very much, it's also pretty obvious when specific bass notes on a very familiar song are completely missing on speakers that give some output down to 35Hz but are plainly audible on good headphones.
And yes, of course I have run an RTA on such music to find out what the exact frequencies are. Bass notes down to around 25Hz are very common in electronic music, and it's also quite common for them to be near sinusoidal in nature - so if the speakers can't reproduce that frequency there are no harmonics to hear so you just hear a silent gap in the bassline.
Nobody can play ? Or nobody can fully appreciate ?
You could say the same about why would anyone bother to release music that goes down to 32Hz when a lot of small bookshelf speakers can only play down to about 50Hz.
At the end of the day the human hearing system can easily hear bass down to about 25Hz as a tone (20Hz is getting pretty ropey) so if you can hear that low and bass is electronically synthesised and can be produced at any frequency desired, some people are going to make music that includes it.
If a lot of people can't hear those lowest notes because their speakers don't go low enough, tough luck for them. If you want to fully experience songs with very low bass frequencies you need speakers that can reproduce them. If you don't care about those very low frequencies that's fine as well, but there will be gaps in the bassline, which personally I find quite annoying.
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I would go with identical subs for simplicity. It will be a lot cheaper to DIY and you will need decent drivers 12" or over IMO to have audible 20-30Hz bass (that isn't just harmonic distortion). Smallest solution will be sealed with a powerful amp. If you intend to use multi sub optimizer you will need a separate DSP channel for each sub woofer location. No personal experience of this amp but the reviews look good and could do 4 subwoofer locations: the t.amp Quadro 500 DSP – Thomann UK
If I was building my own enclosures something like that would be interesting but I think I mentioned already that I have no interest or inclination in building a Sub, nor do I have the time or working space to do it at the moment, hence the current stall in the 3 way build. (No time/working space to work on cabinets, basically, I have all the drivers and most of the design mapped out)
I'm still looking around but leaning towards the second, larger BK model I linked - £410 for a down facing 12" driver in 50 litre sealed enclosure:
Platinum P12300-SB
That's still within my budget and I would be able to pick up a second one in a few months to further flesh out the multi-sub arrangement, but even one would be an improvement on what I have now and a useful stepping stone.
The cabinet is 40x40x46cm and almost exactly the same size as a table that is beside the sofa where it might go in which case it would replace the table and become the sofa side table. It will also easily fit in the corner near the front right main speaker in the other location I'm going to test, and ultimately I would have one in both those locations.
For the sake of only saving £50 the smaller model was only a 10" driver in a 17 litre sealed enclosure and on reflection even with 3 of them they wouldn't have been up to the job of matching up with the 3 way system they would eventually be expected to work with which will be a 110 litre bass reflex with 12" driver tuned to 25Hz.
I'm not convinced that a separate DSP for each subwoofer is really needed with a multi-sub system, a variable phase control and variable low pass filter on each is all that should really be needed to get a good blend between the various woofers and then some global EQ can be applied to the system as a whole to lower the bass level back to neutral and smooth out any remaining bumps with PEQ's. This global EQ to reduce bass drive has the benefit that it ends up reducing the bass drive to the main speakers as well, (which are currently 2 ways and will benefit from this) while still letting them overlap with the subs for modal smoothing.
While I've built many passive speakers I've never really played around with Subwoofers so it will be an interesting exercise going through all the permutations, especially when I have a good measurement and EQ setup available to optimise it. (ARTA and a DEQ2496)
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After doing a bit more searching around I really can't seem to find anything comparable in size/performance to the P12-300SB-DF in the £400 range other than other BK models just above and below it.
There are plenty of subwoofers up to double that price that still only have 8 or 10" drivers for example, or have lower power amps etc... and I can tell just by looking at some of them that they're gimmicky and glossy without necessarily performing all that well. My preference is a simple, honest, solid but no frills design with a wood finish, similar to what I would design and build myself if I actually had an interest in designing a subwoofer.
Also there aren't a lot of choices with a down facing woofer, which while not essential is my preference both from a blend-in-with-the-furniture aesthetics point of view, and also from my preference of having a woofer loaded close to room boundaries, as well as it helping to acoustically filter out unwanted higher frequencies.
So I'm thinking of pulling the trigger on this in a couple of days time unless anyone has any further suggestions to look at under £500 in the way of sealed 12" subs ? I'm actually struggling to find any under £500 that look even half decent aside from the BK stuff.
There are plenty of subwoofers up to double that price that still only have 8 or 10" drivers for example, or have lower power amps etc... and I can tell just by looking at some of them that they're gimmicky and glossy without necessarily performing all that well. My preference is a simple, honest, solid but no frills design with a wood finish, similar to what I would design and build myself if I actually had an interest in designing a subwoofer.
Also there aren't a lot of choices with a down facing woofer, which while not essential is my preference both from a blend-in-with-the-furniture aesthetics point of view, and also from my preference of having a woofer loaded close to room boundaries, as well as it helping to acoustically filter out unwanted higher frequencies.
So I'm thinking of pulling the trigger on this in a couple of days time unless anyone has any further suggestions to look at under £500 in the way of sealed 12" subs ? I'm actually struggling to find any under £500 that look even half decent aside from the BK stuff.
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If I was in your situation I'd probably start looking at 2nd hand subs from the better manufacturers on a UK site like AVforums. You'll probably find something from B&W, Kef etc for the same price as the BK stuff. Wait a few months you'll pick up 3 or 4 of them.
Cheers,
Rob.
Cheers,
Rob.