Multiple bass drivers in single sealed enclosure...

richardkrol · 2nd March 2004, 12:46 PM

One of the things that's not clear to me is the effect of using multiple drivers in a single sealed cabinet.

I was thinking of using multiple 8" seas or scanspeak woofers in a sealed cabinet, and I'd like to know what the effect is, and also which values I should divide or multiply when using calculation sheets.

Is there also something available that replicates a Linkwitz transform circuit but then "off the shelve"?

Furthermore, If I buy a Behringer EMC8000 Mic, which preamp should I use to interface with my computer...is a M-Audio Duo USB up to the task?

Regards,

Richard

Timn8ter · 2nd March 2004, 05:24 PM

Vas and Sd double. Depending how they are wired Le will halve in parallel, double in series. Generally this means a doubling of the cross-sectional area. SPL is +6 in parallel, unchanged in series.

Svante · 2nd March 2004, 07:30 PM

Assuming that

a is the number of elements that are connected in series, electrically,
b is 1 for normal configuration 2 for isobaric configuration and
n is the total number of elements,

Vas1=Vas*n/(b^2)
Bl1=Bl*a
Sd1=Sd*n/b
Re1=Re*a^2/n
Le1=Le*a^2/n

Isobarik mounting meaning mounted in pairs, no more. Index 1 are the new values.

Pjotr · 2nd March 2004, 08:00 PM

Quote:

Originally posted by richardkrol

......

Furthermore, If I buy a Behringer EMC8000 Mic, which preamp should I use to interface with my computer...is a M-Audio Duo USB up to the task?

Regards,

Richard

Have this combo and it works great with a laptop. But I can’t manage the USB duo to work higher than 16 bits @ 48 kHz under Win2K with my measurement software (Audiotester and Sample Champion).

If you want to connect the mic to a regular build in soundcard buy a low cost Behringer mixing console with phantom power like the UB820.

Cheers

richardkrol · 2nd March 2004, 08:09 PM

Thanks all !

Does that mean that say with two drivers a lower f3 point can be had and/or that the excursion of the driver is less for the same spl..?

As for the M-audio duo usb, I am running mac osx. what I like about this unit is that it can interface with the pc and work as a standalone preamp / converter.

regards,

Richard

cadmaniac · 2nd March 2004, 08:33 PM

I used a pair of SS 21W/8555-01 per side in 45 litre sealed boxes, below 200Hz in 4-ways. For LT; I used & highly recommend the Marchand WM8. With a 3-way XM9 & a passive umid-tweet XO; those were phenominal speakers! I prefer Excel woofers (seem clearer) to the Scans.

Svante · 2nd March 2004, 08:37 PM

Quote:

Originally posted by richardkrol
Thanks all !

Does that mean that say with two drivers a lower f3 point can be had and/or that the excursion of the driver is less for the same spl..?

regards,

Richard

With two drivers in a double-sized box, the frequency response will be the same. The maximum output will be +6dB, alternatively, the cone amplitude is halved for a given level.

With two drivers in the *same* box (as you had for the one driver) F3 will *increase*, since Vas is doubled. How much it increases depends on the Vas/Vb ratio.

Dave Jones · 4th March 2004, 02:00 AM

Quote:

Originally posted by Timn8ter
Vas and Sd double. Depending how they are wired Le will halve in parallel, double in series. Generally this means a doubling of the cross-sectional area. SPL is +6 in parallel, unchanged in series.

Can you reconcile that with the info in this thread? Gain when using nore speakers

I would think the SPL would increase by 3db, not 6. Perhaps I need the Dummies (tm) explanation of SPL and sensitivity.

Also, 'splain this to me if you can: I have MTM speakers (Lynn Olson Ariels) that use two mid/bass units with rated sensitivity of 88 and a tweeter that's rated at 90. The cross-over has resistors in it to pad down the tweeter. How can that be? The measured response is nice and flat. I can't reconcile those numbers.

ooheadsoo · 4th March 2004, 02:08 AM

Quote:

Originally posted by Dave Jones
Also, 'splain this to me if you can: I have MTM speakers (Lynn Olson Ariels) that use two mid/bass units with rated sensitivity of 88 and a tweeter that's rated at 90. The cross-over has resistors in it to pad down the tweeter. How can that be? The measured response is nice and flat. I can't reconcile those numbers.

I don't understand what there is to reconcile. The tweeter is more sensitive so they padded it down to bring to the level of the woofer.

Dave Jones · 4th March 2004, 04:16 AM

Quote:

Originally posted by ooheadsoo

I don't understand what there is to reconcile. The tweeter is more sensitive so they padded it down to bring to the level of the woofer.

There are TWO woofers per tweeter.

2nd March 2004, 12:46 PM	#1
richardkrol diyAudio Member Join Date: Mar 2004 Location: Genk, Belgium	Multiple bass drivers in single sealed enclosure... One of the things that's not clear to me is the effect of using multiple drivers in a single sealed cabinet. I was thinking of using multiple 8" seas or scanspeak woofers in a sealed cabinet, and I'd like to know what the effect is, and also which values I should divide or multiply when using calculation sheets. Is there also something available that replicates a Linkwitz transform circuit but then "off the shelve"? Furthermore, If I buy a Behringer EMC8000 Mic, which preamp should I use to interface with my computer...is a M-Audio Duo USB up to the task? Regards, Richard

2nd March 2004, 07:30 PM	#3
Svante diyAudio Member Join Date: Feb 2004 Location: Stockholm	Assuming that a is the number of elements that are connected in series, electrically, b is 1 for normal configuration 2 for isobaric configuration and n is the total number of elements, Vas1=Vasn/(b^2) Bl1=Bla Sd1=Sdn/b Re1=Rea^2/n Le1=Le*a^2/n Isobarik mounting meaning mounted in pairs, no more. Index 1 are the new values. __________________ Simulate loudspeakers: Basta! Simulate the baffle step: The Edge

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Undivided Sealed Enclosure Response With Multiple Drivers...	HsOffRoad	Subwoofers	5	7th October 2007 02:59 PM
Best 10 inch sub drivers for sealed enclosure	brox	Subwoofers	17	14th March 2007 07:40 AM
Multiple drivers in the same enclosure	MJ Dijkstra	Multi-Way	4	20th November 2006 10:01 PM
Calculating EBP for sealed enclosure drivers...	sberube	Multi-Way	2	4th June 2004 08:14 AM
Multiple drivers in same enclosure & resistors for attenuating tweeters	bm_mode	Multi-Way	4	14th October 2001 02:21 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

2nd March 2004, 05:24 PM	#2
Timn8ter diyAudio Member Join Date: Jul 2003 Location: Seattle, WA	Vas and Sd double. Depending how they are wired Le will halve in parallel, double in series. Generally this means a doubling of the cross-sectional area. SPL is +6 in parallel, unchanged in series.

2nd March 2004, 08:09 PM	#5
richardkrol diyAudio Member Join Date: Mar 2004 Location: Genk, Belgium	Thanks all ! Does that mean that say with two drivers a lower f3 point can be had and/or that the excursion of the driver is less for the same spl..? As for the M-audio duo usb, I am running mac osx. what I like about this unit is that it can interface with the pc and work as a standalone preamp / converter. regards, Richard

2nd March 2004, 08:33 PM	#6
cadmaniac diyAudio Member Join Date: Nov 2003 Location: Boston, MA	I used a pair of SS 21W/8555-01 per side in 45 litre sealed boxes, below 200Hz in 4-ways. For LT; I used & highly recommend the Marchand WM8. With a 3-way XM9 & a passive umid-tweet XO; those were phenominal speakers! I prefer Excel woofers (seem clearer) to the Scans.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)