Seas W17EX-002 smallest box volume and crossover freq

bacworth · 27th May 2012, 02:50 PM

What would be the smallest ported box volume you would recommend for the Seas W17EX-002? Tuning frequency recommendations too please?

What crossover frequency would you use when paired with Seas T25CF-001?

sreten · 27th May 2012, 11:00 PM

Hi,

Zaph|Audio

A better cheaper Seas driver combination for a 2 way,
for the reasons explained in the write-up, and his tests.

rgds, sreten.

PeteMcK · 27th May 2012, 11:08 PM

because it's such a low Q driver, (Qts = .26) any vented box is going to have an element of EBS alignment; How low you want to go will determine box size & tuning. 12L @ 45Hz will give an F3 of 48 Hz; 15L @ 43 Hz wil give an F3 of 43Hz.

The driver will need a notch at just under 6Khz, 2Khz looks to be a good xover point

bacworth · 28th May 2012, 12:58 AM

Quote:

Originally Posted by sreten

Hi,

Zaph|Audio

A better cheaper Seas driver combination for a 2 way,
for the reasons explained in the write-up, and his tests.

rgds, sreten.

I already have the drivers from an old Seas Odin kit.

sreten · 28th May 2012, 01:16 AM

Quote:

Originally Posted by bacworth

I already have the drivers from an old Seas Odin kit.

Hi,

Well follow that kit, the only way to make a big difference in
cabinet volume is to make them sealed and use a subwoofer.

Do you have link to the original design ?

rgds, sreten.

PeteMcK · 28th May 2012, 01:21 AM

Odin MK3
that'll give you the notch required, but even if you halve the volume, the MTM is using 2 drivers to make up the drop-off in bass. With a single driver you'll need to deal with this using judicious tuning & baffle step compensation.

bacworth · 28th May 2012, 03:02 AM

The kit was a MTM design and I plan to use this to make 4 individual speaker and buy another 2 tweeters. i.e. single woofer and tweeter in each.

Let assume 12L as the box volume.

bacworth · 09:28 AM

Quote:

Originally Posted by PeteMcK

The driver will need a notch at just under 6Khz, 2Khz looks to be a good xover point

Can you do rough schematic of the crossover? Not sure what you mean by a notch at 6khz. Do you mean a LCR filter. thanks...

sreten · 12:10 PM

Hi,

Its a very tricky driver to use in a 2 way due to distortion
caused by the large peak at 4KHz to 5kHz. D3 at ~ 1.5KHz,
D4 at ~ 1.1KHz and D5 at ~ 0.9KHz will all be bad, indicating
you really need a x/o point lower than around 1KHz.

http://www.clofis.nl/brochures/seas/E0010_W17EX-002.pdf
The seas graph is in a sealed 12L box, note the amount of BSC needed.

I'd use both drivers and the tweeter in a 3 way.

rgds, sreten.

PeteMcK · 28th May 2012, 11:42 PM

re:'rough schematic' - well, you can use the schem on the SEAS site, with the value of L1 doubled for a single driver; then you need to adjust L1 for baffle step, and adjust the attenuation on the tweeter (R2) to compensate.
Yes, notch = LCR filter

27th May 2012, 02:50 PM	#1
bacworth diyAudio Member Join Date: Dec 2001 Location: Australia	Seas W17EX-002 smallest box volume and crossover freq What would be the smallest ported box volume you would recommend for the Seas W17EX-002? Tuning frequency recommendations too please? What crossover frequency would you use when paired with Seas T25CF-001?

27th May 2012, 11:00 PM	#2
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Zaph\|Audio A better cheaper Seas driver combination for a 2 way, for the reasons explained in the write-up, and his tests. rgds, sreten. __________________ There is nothing so practical as a really good theory - Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

27th May 2012, 11:08 PM	#3
PeteMcK diyAudio Member Join Date: Feb 2002 Location: Western Sydney	because it's such a low Q driver, (Qts = .26) any vented box is going to have an element of EBS alignment; How low you want to go will determine box size & tuning. 12L @ 45Hz will give an F3 of 48 Hz; 15L @ 43 Hz wil give an F3 of 43Hz. The driver will need a notch at just under 6Khz, 2Khz looks to be a good xover point __________________ Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency

28th May 2012, 01:21 AM	#6
PeteMcK diyAudio Member Join Date: Feb 2002 Location: Western Sydney	Odin MK3 that'll give you the notch required, but even if you halve the volume, the MTM is using 2 drivers to make up the drop-off in bass. With a single driver you'll need to deal with this using judicious tuning & baffle step compensation. __________________ Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency

28th May 2012, 12:05 PM	#9
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Its a very tricky driver to use in a 2 way due to distortion caused by the large peak at 4KHz to 5kHz. D3 at ~ 1.5KHz, D4 at ~ 1.1KHz and D5 at ~ 0.9KHz will all be bad, indicating you really need a x/o point lower than around 1KHz. http://www.clofis.nl/brochures/seas/E0010_W17EX-002.pdf The seas graph is in a sealed 12L box, note the amount of BSC needed. I'd use both drivers and the tweeter in a 3 way. rgds, sreten. __________________ There is nothing so practical as a really good theory - Ludwig Boltzmann When your only tool is a hammer, every problem looks like a nail - Abraham Maslow Last edited by sreten; 28th May 2012 at 12:10 PM.


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28th May 2012, 03:02 AM	#7
bacworth diyAudio Member Join Date: Dec 2001 Location: Australia	The kit was a MTM design and I plan to use this to make 4 individual speaker and buy another 2 tweeters. i.e. single woofer and tweeter in each. Let assume 12L as the box volume.

28th May 2012, 11:42 PM	#10
PeteMcK diyAudio Member Join Date: Feb 2002 Location: Western Sydney	re:'rough schematic' - well, you can use the schem on the SEAS site, with the value of L1 doubled for a single driver; then you need to adjust L1 for baffle step, and adjust the attenuation on the tweeter (R2) to compensate. Yes, notch = LCR filter __________________ Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency

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