Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[leon douven]

Hello,

I wonder if the acoupower 18" driver would be
a suitable driver for a horn-cabinet.
It seems like a state of the art driver, especially
the suspension looks like it can handle enormous
travel...

What would the perfect horn look like (parameters / size's)
if max spl is the goal, low cutoff 30Hz or even 25Hz...

Regards,
Leon

[leon douven]

sorry I meant, spl

Regards
Leon

[Nathan Lehouillier]

There are no simple answers and I am not an athority on this one but a
good stat is to look at the drivers QTS. A QTS of 2-2.8 is a good Horn driver.

Nate KDS&L

[Walt de Jong]

An exponential horn 3.2 metres long, mouth area 5400cm2, throat area 500cm2. Rearchamber 50 litres. This gives you a resonably flat response down to 30Hz at about 100dB/1w/1m.

Best regards,

Walt

[leon douven]

Hello Walt,

any prediction for max spl?

Regards,
Leon

[Walt de Jong]

What is the maximum powerhandling and lineair x-max?

Best regards,

Walt

[leon douven]

Hi Walt,

this is what I found on the web...

Regards,
Leon

1) High power handling.  2,000 to 3,600W RMS, depending on the application.  2) Flat response.  Both drivers are flat +-1dB to 500 Hz.  Not typical of high power subs... but that way by design.  This extend response allows the drivers to be used with a wide array of crossover frequencies and slopes.  
3) Very low power compression.  Inaudible for most applications.  
4) Super linearity.  100% linear BL product for +18mm of travel in EACH direction.  Proprietary spider and precise details in the surround provide exceptional mechanical linearity and smooth overdrive characteristics.  
5) Extremely low distortion, below the threshold of audibility for most of the output envelope.  
6) We are experts in Acoustic Power Density.  These drivers have the highest low frequency output ever obtained in standard 15" and 18" sizes thanks to 78mm of travel, high power handling and low power compression.  In many applications, one driver can be used where two are being used now.  
7) Relatively simple and bullet proof design.  We believe in the KISS principle.  
Parameters optimized for very low frequency performance.  These drivers can still be used to generate ludicrous amounts of "standard" bass (50-100 Hz) if needed, but they have been designed to excel at very low frequencies, requiring little or no equalization for many properly designed subwoofer applications, maximizing the power available from amplifiers.  

18"
Sd = 0.108 m^2
Cms = 106.6 um/N
Vas = 174 liters
Re = 6.2 ohms
Mms = 305 g See Below
Fo = 28.2 Hz
BL = 23.3 t*m See Below
Qe = 0.62
Qm = 8.90
Qt = 0.58
SPL = 90.5 See Below

The data above is derived from the impedance curves.  Note that the Mms values above includes ALL of the acoustic mass as well, which is substantial in subwoofers.  In addition, the actual BL values for these drivers is about 8% higher than the parameters above.  As a result of both of these measurement artifacts, the calculated SPL 1W/1m dB's are lower than actual SPL's by 0.5 to 1.5dB.  We have provided the actual SPL's in the data above.

Overall Diameter = 462mm
Mounting Holes = ( 6.4mm holes on a 441mm B.C.D.
Cut Out = 425mm ; Maximum thickness of baffle at cut out = 1.25" (32mm)
Weight = approximately 44 Lbs.
Depths assuming "drop in" or "standard" mounting:
Mounting surface to back of driver = 224.50mm
Mounting surface to top of surround roll, full excursion = 48mm
Diameter for the depth above = 345mm nominal.  Suggest you use 355mm to account for the cumulative errors associated with cabinet and grill errors... depending on the application

[Walt de Jong]

Hello Leon,

Using 18mm x-max (one way cone travel) and 3600W powerhandling I get a max. SPL of about 135dB from 35Hz and up. Sounds nice isn't it?

On the other hand, this horn has more volume then 3x Punisher horn. Such a stack of 3x Punisher driven with the same 3600W will produce about 4-5dB more SPL max between 45 and 70Hz. Also the 3x 4" Ciare coil together probably have much less powercompression then 1x Acoupower driver.

Best regards,

Walt

[leon douven]

Hi Walt:

can you stand 1 more??

what can we do to go down to 25Hz...

how long must the horn be... mouth area, throat area,
rear chamber? prediction for max spl in this case?

best regards,
Leon

[Mark "Bass Pig" Weiss]

I too looked at the Accupower drivers. They look impressive on paper, but I would be cautious about using a paper cone driver in a horn application. I went with the Bassmaxx ZR18s for their efficiency and stronger cone assemblies.
Both drivers are lightyears ahead of conventional drivers, and will replace numerous 18" drivers of conventional build with a single driver for same SPL, but for horn loading, there may be advantages to the ZR18. They are the first speaker that I have not been able to destroy. I usually destroy new drivers during free air low power testing. Not these. Horns pressent a peculiar mechanical stress on cones. Paper will not stand up to this stress for very long if the driver is fully driven at full power.