54 Hz sound

[a007udio]

Hello.

Is this a stupid idea?

PA 18 inch sub (B&C) in 110 l closed box (QTC 0.7) -3dB 54 Hz.


How will this sound?

Any idea.

 

[Cal Weldon]

Like a dance club.

Cal

 

[Illusus]

they'll sound great if all you like to listen to is Venga boys

... could be good for rock. as long as they're smooth from Fb. rock likes sounds good with a bit of upper bass lift and doesn' t need low extension. But why not build something good over-all?

 

[Illusus]

actually...since it's sealed, it should have a nice smooth roll off that the room will augment. depends on the room. you could try a Linkwitz transform if the driver can handle it. what are your room dims?

It's not a stupid idea at all.

 

[a007udio]

my room dimensions are 7m x 4m.

I listen jazz, rock, ..

So what is the diference betwen scan speak 54 Hz and PA driver 54 Hz. way do you think PA driver is good only for dance club music. I was listen some PA drivers in hi-fi and i must say that in some aeras are way better than hi-tech drivers like Vifa , Scan Speak ...

So i would like to give a chance to this driver but im afraid that 54 Hz would be to big compromise.

 

[Cal Weldon]

I like the sound of PA drivers also. They may not be as accurate as some of the home stuff but you get a lot of bang for your buck.
Cal

 

[thoriated]

With some electronic eq (e.g. two cascaded first order shelving filters) & enough amplifier, you can move the -3db point as low as you want given the limitations of the particular woofer's suspension linearity below resonance & whether it has sufficient Xmax & power handling to reach the target SPL in the extended lf range.

 

[Illusus]

I'm using PA woofers and love it...big 'ol JBL 15"....Some are better than others. I was just kidding around in the earlier post.

These drivers usually like a large box...max flat sealed may end up in the 300 liter range. However, if you use the smaller box you may be able to use a Linkwitz transform...iff the driver can handle a bit of overexcursion. Sounds great though.

I also think that you may be surprised with 54Hz tuning anyway...It'll be much lower in room. Build it, if you doesn't go low enough for you, add an aperiodic vent...if you don't like that, port the f'r. Once you have the box it's not too hard to play with different alignments.

 

[a007udio]

It sims that alot of peoples like PA drivers. For me it have more lively sound.

I would like to use Linkwitz transform but i cant becouse i would like to use only one integratet amplifier. So no electronic eq and stuff like that.

How many room gain i could expect? If they will play flat from 45 Hz in room im perfectly satisfied. Is there any program to simulate room gain?




Thanks

 

[Rademakers]

http://www.diyaudio.com/forums/showthread.php?postid=634091#post634091

Mvg Johan

 

[BobEllis]

I would like to use Linkwitz transform but i cant becouse i would like to use only one integratet amplifier. So no electronic eq and stuff like that....

Seriously consider giving the sub its own amp. If it's not a dual voice coil driver, you could only use it on one channel anyway. The inductors required to get a suitably low crossover will be huge, expensive and have relatively high DC resistance, causing some shift in your alignment.

Plate amps are fairly inexpensive from a variety of sources, or you could make a 200W bridged/parallel chip amp (National's LM3886 app note provides a suitable circuit that should be sufficient for subwoofer duty.) If you made you own plate amp on a couple of flat section heat sinks like Steve at apexjr.com has it would might even cost less than good quality inductors.

Count me as a member of the high quality PA driver subwoofer fan club. I run a pair of JBL 2245Hs (18") in ~250L ported cabs. They sound great and can take anything I can throw at them, but with the EQ required each needs 500 Watts minimum for headroom. Having two subs in non symetrical locations (mono signal) really helps smooth the response in my room.