Best Drivers for 40 - 170 Hz Sealed Box ? - diyAudio
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Old 1st February 2007, 03:35 AM   #1
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Default Best Drivers for 40 - 170 Hz Sealed Box ?

I am planning a new speaker system and have everything sorted except the 40 - 170 Hz range for a sealed box configuration.

The problem is I need a very fast transient response so I am looking at a single 10", 8" (probably too slow) or 2 x 6 1/2" up to 4 x 5 1/2".

Any thoughts?

Mark
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Old 1st February 2007, 06:47 AM   #2
Nisbeth is offline Nisbeth  Denmark
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Have a look at the Vifa MA26WR (datasheet available from madisound) or maybe the Seas L26.


/U.
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Old 1st February 2007, 10:12 AM   #3
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I think a 26 will be too slow, they will go low enough, but not keep up with the the top end.

My order of preference as:

1. Single Audio Technology Skanning Flexunit 8"
2. Twin Audio Technology Skanning Flexunit 6" (very expensive)
3. Single Scan Speak 2iW8554
4. Twin Peerless 830874
5. Single or twin Scan Speak 18W8351
6. Twin Scan Speak 15W8351
7. Four Vifa P13-00-008 (no longer in production)

Obviously very expensive drivers, but I no experience with these, so I am asking those who have used them and what they think will work best for this application.

The size of the sealed box is not important at this stage, so I can design the speaker to fit what is necessary. But it has to be sealed as I am using a Thor varient for below 50 or 40 Hz.

Mark
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Old 1st February 2007, 01:05 PM   #4
Navy_44 is offline Navy_44  Poland
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What does "fast" mean to you?

If "fast" means an impulse response of a raw woofer that ends quickly, then what you ask for is a woofer with SPL extended as high as possible, however if you cross the woofer at 170Hz, the filter will dominate the impulse response of the LF subsystem and you are not going to see much difference between 18cm and 26cm drivers. The higher frequencies will be reproduced by the midrange and tweeter anyway. There are many 26cm drivers suitable for a moderatly sized closed box with low f3, with piston-like behavior up to 500Hz region and higher (Seas L26RFX/P, Dayton RSS265HF-4) so using them below 170Hz is not an issue from the point of wiev of the impulse response of the whole system.

On the other hand "fast" may also mean "tall order HD and IMD enriched" - usually these components of the musical instrument's spectrum are responsible for "speed" and adding some more by the woofer's distortion may even make the sound "faster". In such case small drivers are definitely better than larger ones as they tend to distort more even at lower SPL levels.
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Old 1st February 2007, 01:34 PM   #5
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Fast as in "Transient Response", hence a closed box as opposed to a vented box. TL and horns are fast but not in this application. Once the note stops, I don't want the driver to keep oscillating. Stop as dead as possible, nothing to do with the crossover, just the characteristics of the driver.

26 cm drivers have too much mass therefore slow, many smaller drivers will have the same mass and a higher cone cm and less distortion, and a higher spl. The laws of physics, they move more air better for a given power usage and at less distortion, the only problem in a home environment as opposed to a live venue is the phase shift with multiple drivers. At 20 metres in a live venue, it is not a problem.

Hence my question for a driver between 50 and 170Hz and be as fast as a normal mid. Normally this range is covered by a woofer to 100Hz and a Sub below that!

A tough one, thats why I'm looking at the Flex units, but I have no experience with them.

I can do a bipolar in a push - push as well, this also counteracts the 6dB baffle step. This will be one of the prototypes I do before final configuration, but I want to start with the best possible driver for this frequency range.

Mark
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Old 1st February 2007, 01:51 PM   #6
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Manufactures publish a number of specs for thier speakers except the time it takes for their speaker to stop moving after a the note has stopped.

I do not have the resources to buy and test every driver I am looking at, configure it in the way I want to, test it and then go onto the next one.

The only hint I have from spec are the cone, area, mass and inductance to work off, but even then, its just a guess without a measurment.

If I can work this out from manufactures spec, please tell me.

Thanks, Mark
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Old 1st February 2007, 02:31 PM   #7
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What your talking about is myth and the ideology of something that is close to perfect is perfect. Doesn't work like that with audio very often though.

Not poking fun because its easy to turn all this into black and white and ignore the grey. But for the range your looking at covering and if you've got the option then I'd suggest a rethink regarding a couple of little 6"/8" mid/woofers and instead look at big Sd and balanced BL/Mms.

I've heard 12's and 15's sounding so right that I'd never consider using smaller drivers given a lack of size constraints.
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Old 1st February 2007, 03:15 PM   #8
EspenE is offline EspenE  Norway
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Quote:
Originally posted by Oz_Audio

If I can work this out from manufactures spec, please tell me.

Yes, you can. It's the inductance. Cone mass and magnet size has nothing to do with it.

See excellent white paper on woofer "speed": http://www.adireaudio.com/Files/Tech...ooferSpeed.pdf

And on group delay in woofers (often perceived as "thightness"): http://www.adireaudio.com/Files/Tech...GroupDelay.pdf
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Old 1st February 2007, 03:26 PM   #9
AR2 is offline AR2  United States
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You might want to check PHL. I do not think that many people have experience with their woofers, their mids are much more used. If it is to judge by mids - awsome speakers. They make very sensitive woofers - it might be interesting to try. http://www.phlaudio.com/
With a seald box higher sensitivity is always welcome. Since your are not looking for extended bottom end than you could have a great choice in drivers. Faster drivers = higher sensitivity drivers in my mind.
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Old 1st February 2007, 03:40 PM   #10
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Thanks, good reading.

Mark
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