Steve Callas has offered up a lot of good advice in this thread. You can get deep DEEP bass out of a 15 or even a 12. To get high SPL *and* deep bass, just add more drivers.
While a 32" woofer may impress your friends, four 15s will do the job cheaper and probably better.
Making bass is all about moving air. The size of the piston is almost irrelevant.
:: PB ::
While a 32" woofer may impress your friends, four 15s will do the job cheaper and probably better.
Making bass is all about moving air. The size of the piston is almost irrelevant.
:: PB ::
4fun said:
Yes, that's true. The problem is that 90% of the world doesn't understand that xmax is just as important as SD.
Show 10 people an eight and a 6.5" woofer, and they'll say that the eight makes more bass. Yet woofers like the Adire Extremis can easily put out as much bass as many 8s and 10s.
XMAX rules.
:: PB ::
A lot of people say that low xmax / big sd sounds better than big xmax / small sd. Pick your poison.
The 'Steve Callas' subs don't really win against sealed subs in the low bass area - again due to the vented subs roll off at 24dB / oct the sealed will win in extension at max spl. (below ~7.6Hz)
Also the size of the ports does become a problem as power gets higher. Group delay is also pretty messy compared to the sealed.
I think my idea of ultra low bass is different to the 'usual' 15Hz stuff, hence my opinion that sealed seems better.
Cheers,
Rob.
The 'Steve Callas' subs don't really win against sealed subs in the low bass area - again due to the vented subs roll off at 24dB / oct the sealed will win in extension at max spl. (below ~7.6Hz)
Also the size of the ports does become a problem as power gets higher. Group delay is also pretty messy compared to the sealed.
I think my idea of ultra low bass is different to the 'usual' 15Hz stuff, hence my opinion that sealed seems better.
Cheers,
Rob.
Attachments
I don't think xmax is a substitute for piston area. The figures will show you can achieve the same amount of air movement, but take into account the velocity and resulting g-force on the cone.
Whatever technology was used in the 6.5" driver that knocks of 8 and 10" units can be applied to larger ones.
Geoff.
Whatever technology was used in the 6.5" driver that knocks of 8 and 10" units can be applied to larger ones.
Geoff.
Hi,
If we are going to trade smaller SD for grater Xmax we will need longer voice coil and wider surround. Longer coil will result in decreased sensitivity as very little part of coil is in gap. Greater distorsion due to self inductance witch will vary with excursion polarity/rate. Of course distorsion can be reduced by using shorting rings under and obove gap.
Low sensivity can be compensated with more power of course, but with power comes comes compression due to voicecoil heating.
A look at kippel and/or dumax tests show how good/bad some woofers are, very few high Xmax woofers have a high degree of linearity within its advertised Xmax.
The need for big surround on extreme Xmax woofers worries me, as the sorround gets bigger the cone gets smaller for a given size woofer. We now have a woofer that has a great deal of its radiating area from the surround, again increasing distorsion.
It would be nice to watch surround flex during excursion in different working conditions with a syncronised lightsouce.
If we are going to trade smaller SD for grater Xmax we will need longer voice coil and wider surround. Longer coil will result in decreased sensitivity as very little part of coil is in gap. Greater distorsion due to self inductance witch will vary with excursion polarity/rate. Of course distorsion can be reduced by using shorting rings under and obove gap.
Low sensivity can be compensated with more power of course, but with power comes comes compression due to voicecoil heating.
A look at kippel and/or dumax tests show how good/bad some woofers are, very few high Xmax woofers have a high degree of linearity within its advertised Xmax.
The need for big surround on extreme Xmax woofers worries me, as the sorround gets bigger the cone gets smaller for a given size woofer. We now have a woofer that has a great deal of its radiating area from the surround, again increasing distorsion.
It would be nice to watch surround flex during excursion in different working conditions with a syncronised lightsouce.
I think this is what you are after
http://www.pipeorgansound.com/sound_images.htm
http://www.pipeorgansound.com/wall_of_sound.htm
An externally hosted image should be here but it was not working when we last tested it.
http://www.pipeorgansound.com/sound_images.htm
http://www.pipeorgansound.com/wall_of_sound.htm
Hi,
Let me dig in to this as well.
Isn't a Lab Horn a very small horn compared to what Andrew probably was suggesting?
I am a true horn beleaver myself, if I only had the space. I have over the time built a few basshorns of moderate format and the best had good response down to ~25Hz into pi loading in room. That itself is not impressive but the soundquality certanly was.
If we hade the space it would be possible to build lets say a 15Hz horn that could easily reach down to 10Hz with good sensitivity.
Like this:
http://www.royaldevice.com/custom.htm#THE REAL TOTAL HORN
This has been linked to many times before but I consider it to be a extraordinary system. Imagine 110dB/1W sensitivity, 16 18" woofers that share the load, compression must be nonexistant. Response well down to 10Hz.
Let me dig in to this as well.
Isn't a Lab Horn a very small horn compared to what Andrew probably was suggesting?
I am a true horn beleaver myself, if I only had the space. I have over the time built a few basshorns of moderate format and the best had good response down to ~25Hz into pi loading in room. That itself is not impressive but the soundquality certanly was.
If we hade the space it would be possible to build lets say a 15Hz horn that could easily reach down to 10Hz with good sensitivity.
Like this:
http://www.royaldevice.com/custom.htm#THE REAL TOTAL HORN
This has been linked to many times before but I consider it to be a extraordinary system. Imagine 110dB/1W sensitivity, 16 18" woofers that share the load, compression must be nonexistant. Response well down to 10Hz.
4fun said:
I love horns. I'm not knocking horns. But answer the question. For ultra-low bass, what is the most efficient?
You know what the answer is, so don't dodge the question.
And besides, what are you going to PUT in this uber-horn? A driver with an FS of 25hz? That's not going to cut it. To get that low, you'll need a driver with an FS of 8hz and a qts of 0.25. Drivers like that DON'T EXIST.
:: PB ::
Merry Christmas!
FYI, ThomasW, the 'Cult of the Infinitely Baffled' forum owner is the designer/owner of the '12 Dancing Shivas' IB, though TN's twelve TC Sound's 15" IB is what inspired him to do it.
WRT an efficient sub horn, just running the numbers, a single Shiva in a M = 0.5 Fc = 31 Hz horn with a 10-96 Hz BW calcs a ~48.7% eff. (~108.9 dB/W/m), so with two you could shorten it somewhat without any loss. Either way it should fit in a basement or attic.
More entertaining though would be to mass load a pair to 11 Hz/Qes = 0.8 with wooden discs and make it an optimized BLH with a 4.4 - 27.5 Hz BW for true sub duty. This way you could have the drivers visible in a tiny bipolar box, looking for all the world like Carver's latest n' greatest min-sub, then have the mouth concealed at the other end of the room............
At a calc'd ~40.5% eff. (~108.1 dB/W/m), the diaphragms would be barely moving while the room/house was collapsing around you during a space shuttle launch.
Cheers!
GM
FYI, ThomasW, the 'Cult of the Infinitely Baffled' forum owner is the designer/owner of the '12 Dancing Shivas' IB, though TN's twelve TC Sound's 15" IB is what inspired him to do it.
WRT an efficient sub horn, just running the numbers, a single Shiva in a M = 0.5 Fc = 31 Hz horn with a 10-96 Hz BW calcs a ~48.7% eff. (~108.9 dB/W/m), so with two you could shorten it somewhat without any loss. Either way it should fit in a basement or attic.
More entertaining though would be to mass load a pair to 11 Hz/Qes = 0.8 with wooden discs and make it an optimized BLH with a 4.4 - 27.5 Hz BW for true sub duty. This way you could have the drivers visible in a tiny bipolar box, looking for all the world like Carver's latest n' greatest min-sub, then have the mouth concealed at the other end of the room............
At a calc'd ~40.5% eff. (~108.1 dB/W/m), the diaphragms would be barely moving while the room/house was collapsing around you during a space shuttle launch.
Cheers!
GM
GM said:Merry Christmas!
FYI, ThomasW, the 'Cult of the Infinitely Baffled' forum owner is the designer/owner of the '12 Dancing Shivas' IB, though TN's twelve TC Sound's 15" IB is what inspired him to do it.
WRT an efficient sub horn, just running the numbers, a single Shiva in a M = 0.5 Fc = 31 Hz horn with a 10-96 Hz BW calcs a ~48.7% eff. (~108.9 dB/W/m), so with two you could shorten it somewhat without any loss. Either way it should fit in a basement or attic.
More entertaining though would be to mass load a pair to 11 Hz/Qes = 0.8 with wooden discs and make it an optimized BLH with a 4.4 - 27.5 Hz BW for true sub duty. This way you could have the drivers visible in a tiny bipolar box, looking for all the world like Carver's latest n' greatest min-sub, then have the mouth concealed at the other end of the room............
At a calc'd ~40.5% eff. (~108.1 dB/W/m), the diaphragms would be barely moving while the room/house was collapsing around you during a space shuttle launch.
Cheers!
GM
GM, I just wiped a little drool off my chin
Seriously though, kudos for modeling the subs!
Hi Patrick,
However, I can assure you that the EFFICIENCY (not sensitivity) of a correctly proportioned horn will always be higher than a correctly proportioned box speaker.
Q.
how far below Fs can a horn work?
I have heard the horn works well down to about half Fs with some of these back loaded horns fitted to the small 6inch and 8inch drivers.
If this were the case then my Tannoys with Fs=28Hz may well reproduce well down to 20Hz and some response down to 14Hz?
Help, my design is almost finished and production has started (at the mouth end).
Corner loaded, mouth=3.6sqm (equivalent to 29sqm for 18Hz), throat = 750sqcm and 8.5m long.
this is an unfair suggestion/request, when you already know that hornresp has a maximum Mouth area of 10sqm.
However, I can assure you that the EFFICIENCY (not sensitivity) of a correctly proportioned horn will always be higher than a correctly proportioned box speaker.
Q.
how far below Fs can a horn work?
I have heard the horn works well down to about half Fs with some of these back loaded horns fitted to the small 6inch and 8inch drivers.
If this were the case then my Tannoys with Fs=28Hz may well reproduce well down to 20Hz and some response down to 14Hz?
Help, my design is almost finished and production has started (at the mouth end).
Corner loaded, mouth=3.6sqm (equivalent to 29sqm for 18Hz), throat = 750sqcm and 8.5m long.
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