I was having a discussion with a friend of mine about what type of enclosure would be the loudest for a single given frequency, i.e. 50hz.
I settled on some type of double tuned bandpass, he went with a simple ported alignment.
So, which enclosure type can be crowned loudest of them all? I know there are much more knowledgeable pros on this forum that could answer this without even breaking a mental sweat.
TIA,
MEXXX
I settled on some type of double tuned bandpass, he went with a simple ported alignment.
So, which enclosure type can be crowned loudest of them all? I know there are much more knowledgeable pros on this forum that could answer this without even breaking a mental sweat.
TIA,
MEXXX
This is just my opinion and experience:
A well tuned Bass-Reflex (ported) can be more loud than a bandpass enclousure.
I have a bandpass subwoofer and a BR one. Both have the same driver and the BR is louder. The bandpass only gets lower frequencies than the BR.
Remember, this is my experience with my enclousures.
Regards
A well tuned Bass-Reflex (ported) can be more loud than a bandpass enclousure.
I have a bandpass subwoofer and a BR one. Both have the same driver and the BR is louder. The bandpass only gets lower frequencies than the BR.
Remember, this is my experience with my enclousures.
Regards
Surely a horn's more efficient ('LOUDER') than either
.Bandpass would probably be his best bet (They are big on one note wonders in Finland and they are starting to use a lot of bandpass stuff), Bass reflex is much simpler to do though and a lot more tollerant of errors. Horns would be ideal but its usually a space issue, even a folded horn to hit 50Hz is pretty damn big, try squeezing one in a car! Although you may well just get one in a van.
AFAIK, a compression driven tapered pipe, i.e. a type 1 (sealed back) bandpass tuned with a tapered (to reduce the length and further load the driver) vent to 50Hz. The driver will have to be custom made to get the near 50% efficiency it's capable of and the power handling required to reach the SPL required to 'blow the doors off' 
the competition.
If you must use a readily available point source driver, then find the lowest Fs, Qes, and highest Pe, Xmech driver available for its frame size. To gain acoustic efficiency, use a driver size that yields the highest compression ratio that doesn't 'lay down' from thermal power compression, rip something, or burn up in the time frame of the 'run'.
IOW it's only good for as many 'runs' as required by the rules, so at a glance an 18" HE driver with a high Mms and super strong motor to keep Qes low is the 'Hot Ticket'. Remember, the highest efficiency racing motor for a given set of rules/conditions blows as it crosses the finish line so design it for easy driver replacement between 'runs', yet still seals completely as any leaks will 'kill' most of its efficiency.
GM
the competition.If you must use a readily available point source driver, then find the lowest Fs, Qes, and highest Pe, Xmech driver available for its frame size. To gain acoustic efficiency, use a driver size that yields the highest compression ratio that doesn't 'lay down' from thermal power compression, rip something, or burn up in the time frame of the 'run'.
IOW it's only good for as many 'runs' as required by the rules, so at a glance an 18" HE driver with a high Mms and super strong motor to keep Qes low is the 'Hot Ticket'. Remember, the highest efficiency racing motor for a given set of rules/conditions blows as it crosses the finish line so design it for easy driver replacement between 'runs', yet still seals completely as any leaks will 'kill' most of its efficiency.
GM
.
Charles,
This would require the rear pipe to be 1WL of 50Hz, probably making the speaker too big for a vehicle, and more importantly, may not load the driver as much as a compression chamber without cancelling out the increased gain, and why I didn't consider it. Only one way to know for sure though since I can't think of an accurate way to sim it with existing programs.
Mexxx,
I was thinking of the late, great Aura 1808, but at a glance the Maelstrom looks like a good one to experiment with at low power, at least initially, to keep from popping it. You can model it in MJK's FLH MathCad worksheet if it's still available (ignore the HF response portion), concentrating on getting the highest Q peak at 50Hz at a ~10:1 CR. I assume it can be simmed in Hornresp also. I've never tried to do this, so don't really know what to expect in a given size. I figured it's already been done, but your Q implies either that this is a 'road not yet taken' or already known to be a 'dead end' in audio 'drag racing'.
GM
This would require the rear pipe to be 1WL of 50Hz, probably making the speaker too big for a vehicle, and more importantly, may not load the driver as much as a compression chamber without cancelling out the increased gain, and why I didn't consider it. Only one way to know for sure though since I can't think of an accurate way to sim it with existing programs.
Mexxx,
I was thinking of the late, great Aura 1808, but at a glance the Maelstrom looks like a good one to experiment with at low power, at least initially, to keep from popping it. You can model it in MJK's FLH MathCad worksheet if it's still available (ignore the HF response portion), concentrating on getting the highest Q peak at 50Hz at a ~10:1 CR. I assume it can be simmed in Hornresp also. I've never tried to do this, so don't really know what to expect in a given size. I figured it's already been done, but your Q implies either that this is a 'road not yet taken' or already known to be a 'dead end' in audio 'drag racing'.
GM
Interesting, I knew they had been making them, but I thought I read that they had ceased production awhile back. Anyway, if it's still being built to Aura's specs, then it's pretty awesome. I built a dual 1808 sub for a small cinema and it was hitting DD ref/20Hz ~45ft back with 2kW on tap.
GM
GM
The question is simpler if you take the car out of the equation - it would *almost* certainly be the horn that would win, but it would also be huge.
Also normally you would expect a bandpass to be louder than vented, however, in this case you could design what would otherwise be a very poor vented box which is large and has high tuning, resulting in a high q sharp peak at 50 Hz tuning. At this point it might be louder than a bandpass.
In fact when you consider that the vented box option is smaller than any of the other options (excluding sealed), you may get the most SPL out of vented boxes simply by designing a nasty 50 Hz peak and by using a pile of 18" ultra high excursion drivers with ridiculous power amps.
I can't really say if this is louder than what others have suggested, but it *might* be. You would have to consider the specific drivers, the size of the boxes, hence how many of them you could fit in the car, power in the amps, etc.
It comes down to
bigger boxes to get more out of the driver
vs
a larger number of smaller boxes and more VD and power
Also normally you would expect a bandpass to be louder than vented, however, in this case you could design what would otherwise be a very poor vented box which is large and has high tuning, resulting in a high q sharp peak at 50 Hz tuning. At this point it might be louder than a bandpass.
In fact when you consider that the vented box option is smaller than any of the other options (excluding sealed), you may get the most SPL out of vented boxes simply by designing a nasty 50 Hz peak and by using a pile of 18" ultra high excursion drivers with ridiculous power amps.
I can't really say if this is louder than what others have suggested, but it *might* be. You would have to consider the specific drivers, the size of the boxes, hence how many of them you could fit in the car, power in the amps, etc.
It comes down to
bigger boxes to get more out of the driver
vs
a larger number of smaller boxes and more VD and power
wasn't aware that he wants to use it in a car. In this case it is definitely out. I just thought he was looking after some one-note noisemaker. If it were to be used outside it would definitely work but it might be quite large and I do neither know what it's efficiency would actually be, nor do I know how to determine best taper and/or compression ratio at the moment. And it's radiation diagram would be a figure of eight.
Regards
Charles
Actually it is the car part of the equation that makes the horn the clear winner. While a freestanding horn often requires a larger box than other designs, when you factor the cabin gain of an automoble into the design process the size required of a horn can be drastically reduced. My AutoTuba horn measures 14x14x32 inches, making it no larger than many direct radiator or bandpass subs, yet in vehicle measured response averages 100dB/watt from 20 to 200 Hz, 105dB from 45 to 200 Hz. When you then factor in the build cost of as little as $60 US (including driver) the other alternatives come up woefully short.
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