which subwoofer for 250W@4ohms class D amp?

"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.

An externally hosted image should be here but it was not working when we last tested it.


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 ;) !
 
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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,
 

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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,
 

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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.
 
Tank you everybody !!!!!!!
I entered the speakers you've talked about in my previous table (the -supposed- best one on the top).
The values have been calculated only with T&S parameters for Bass Reflex (Bessel) : I don't know if they are far from reality or not........
I don't know if 4th order bandpass would be a good solution too...
And what do you think about Monacor SPH390TC in bessel BR ?

An externally hosted image should be here but it was not working when we last tested it.
 
Tank you everybody !!!!!!!
I entered the speakers you've talked about in my previous table (the -supposed- best one on the top).
The values have been calculated only with T&S parameters for Bass Reflex (Bessel) : I don't know if they are far from reality or not........
I don't know if 4th order bandpass would be a good solution too...
And what do you think about Monacor SPH390TC in bessel BR ?

An externally hosted image should be here but it was not working when we last tested it.

FYI: To make a true 'Bessel' ported box, you need drivers with a Qts of close to 0.33.

b:)
 
FroggySeven, can't you use the Eminence Legend BP102, in all similar to the Monacor SPH390TC, only 92.0 dB/2.83V/m (E) vs. 95.0 dB/2.83V/m (M), smaller basket 10" vs 15", and a smaller enclosure?
Certainly that with a big enclosure my choice would be different as bjorno shows 213 L for the Monacor.
Also check the new BEYMA 10BR60 v2011 with 90.0 dB/2.83V/m.
Also consider that, when the footprint/size of the enclosure (VB) is small plus the price of the drivers you can double (2x) the drivers and add 6dB's to the total output/sensitivity.
 
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I must admit I don't understand what "tapped horn" or "PPSL" is.

bjorno : I think I have understood on the picture what is " T-TQWT with sloping FR ".
I think this would be really funny in a horizontal position with a glass table on !!!
But I am not able at all to make the plans...
Which speaker do you used ?
 
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I must admit I don't understand what "tapped horn" or "PPSL" is.

bjorno : I think I have understood on the picture what is " T-TQWT with sloping FR ".
I think this would be really funny in a horizontal position with a glass table on !!!
But I am not able at all to make the plans...
Which speaker do you used ?

Hi, Your idea of a horizontal deign would work well with two folds..I used the first driver in you performance/prize list: The Monacor SPH390TC and this name is also stated in the HR Input screen.

b:)
 
FroggySeven, congratulations for your new future project build.
Hope you like the drivers. A little big for me, but without any more components in your system to match with it's going to be funny to watch how it will end up. A system like that it's going to require lot's of space.:D