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-   -   which subwoofer for 250W@4ohms class D amp ? (http://www.diyaudio.com/forums/subwoofers/216026-subwoofer-250w-4ohms-class-d-amp.html)

FroggySeven 12th July 2012 10:34 AM

"SOLVED" : 38cm subwoofer for only 250W@4ohms amp
 
[ this first message have been edited twice :
1/ Considering the following answers (thanks a lot for your help :) !!! )
2/ when I've made my decision]

I begin to built my home-project with the sub-woofers, using a 2x250W@4ohms Tripath amp.
I don't care of the upper cut frequency : I would choose the "(grave)medium" after.
Of course, the smaller, the better... But it's not the main problem for me up to 150L (why not bigger, if it is worth).

Less than 300€ for one speaker, and down to 30Hz would be nice.
As I will use an equalizer, "down to 30 Hz" doesn't mean -3db but just the max SPL between 30 & 40Hz with 250W@4ohms !
[As 250W is quite small, it means max sensitivity between 30-40Hz for all the loudspeakers too.]
>>>>>> false !!!!!! Xmax is important too, even with only 250W

Here is a table of values for (Bessel) Bass Reflex. Don't know if 4th order pass band or TQWL or ... would be better for this.

http://img26.imageshack.us/img26/6151/tableauhp.jpg

Finally, even if my thougts about sensibility was quite false, I have chosen two SPH390TC
(even if it's a steel, no ventilated basket and needs an quite important volume for Bessel BR...)
...because I hope to use experience of others ;) !

Inductor 13th July 2012 01:09 AM

Do you mean 30Hz -3dB's/F3 or other. Is that car or home?

FroggySeven 13th July 2012 09:06 PM

Thank you to try to help me.

It's for home, so no problem up to 150L (but the smaller, the better...and why not bigger if it is worth)

As I would use a egalizer, I just want the max SPL with 250W at 30Hz
(as 250W is quite small, means the max sensitivity at 30Hz. Is 90db/1W/1m possible ???)

zuki 13th July 2012 09:56 PM

this woofer was 99.00 yesterday.
but no longer a good deal.
Dayton Audio DVC310-88 12" DVC Series Subwoofer 295-185

tb46 13th July 2012 09:56 PM

2 Attachment(s)
Hi FroggySeven,

How about a tapped horn using the B&C 10NW64, it should be fine from 30Hz to 120Hz (this is simulation only, no enclosure design)? Guessing, it would be about 125 L external volume.

Regards,

Djim 14th July 2012 01:23 AM

Hi Oliver,

Maybe you should check the acoustic pressure below 40Hz (the Fs of the B&C is above 1/2 wavelength).

tb46 14th July 2012 02:35 AM

2 Attachment(s)
Hi Djim,

I think it is within reason :-) ; see e.g.: the attached Hornresp plots for the B&C 10Nw64 and the Eminence 3015LF in the SS15. I know you don't like to see the Fs that high versus the lower end of the bandpass, but all the inital work on tapped horns seemed to indicate, that there is nothing wrong with designing a TH that way. FroggySeven has set some difficult parameters: 30Hz-3dB / 90dB/1W/1m / <150L / <300Euro / 250W, maybe you have a better suggestion.

Regards,

Djim 14th July 2012 04:02 AM

Hi Oliver,

What I like is not important :-). All I can see is the predicted response and predicted max output for the SS15 are both not reached in real measurements ;-).

I agree that FroggySeven has set out parameters that are difficult. 150 litres and 90dB at 30 Hertz. It can be reached with a dual 12” setting in a basreflex (maybe in a PPSL setting). Look for 12” drivers with an Fs of 25-30Hz, enough sensitivity down low and a motor/suspension that can handle 75 litres per driver with 30-34Hz tuning. For instance the old Pioneer (Premier in US) TS-W12 can do such job.

tb46 14th July 2012 04:21 PM

2 Attachment(s)
Hi Djim,

"...the old Pioneer (Premier in US) TS-W12 can do such job."

So can two JBl GTO1214, maybe as a PPSL.

Regards,

Djim 15th July 2012 02:24 AM

Quote:

Originally Posted by tb46 (Post 3092035)
So can two JBl GTO1214

Sure they can :-)

https://lh4.googleusercontent.com/-w...s_01.jpg?gl=NL


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