Subwoofers

[Dogbert]

What do you know about the Adire Audio - Rava subwoofer ?
I've seen many good reviews about it in www.audioreview.com as well as other places.
Seems like a real killer for $400, especially since people are saying it's better than subs worth more than a grand.

KvH ?

edit: In the manual it says that the rava goes all the way down to 27Hz...

[isochar]

Other place to go is:

https://www.svsubwoofers.com

[Dogbert]

Heard many good things about them but they cost a lot more.
Since I live in Israel, the final price of a sub is:

Base price + around 60% tax + shipping

This is one big ouch!

[Greebe]

These subs look quite nice for the $$. Major difference between it and the SE version appears to be a slightly lower peak RMS power (250 vs 200) and the High/low pass Linkwitz-Riley filters (optimized for excellent transient response).

Also note that this sub has a very low Q. This is excellent for Jazz/Classical music, but if your looking for a punchier bass neccessary for Pop/Rock a Q of 1.0 or higher is really needed.

[KvHagedorn]

Haven't heard the Adire. Listen before you buy..

[Laurie]

Greebe, what is 'Q' ? I read through those links above and links from those as well but could find nothing on it except for a listing in the specs. It seems that subwoofers are an important part of getting that 'theater' feeling and I'm going to have to spend some time researching this one.

Our basement suite tenant moved out a few months ago and we are going to take over the space for a dedicated home theater room. I'm going to miss the extra income but we really only built it for our kids to use and they're gone now. I digress, sorry.

So far we have mostly old stuff (some of it REALLY old) and have to aquire a DTS amp or receiver (my 30 year old Marantz won't cut it anymore ). The plan is to use our 30 year old JBL's with a new subwoofer and two new rear speakers but I'm not sure if this will work. The TV is a fairly old 32" Sony but replacing this is not a consideration right now. A Panasonic DVD-RV31 and a good 10 year old Sony VHS round out the bits needed I think.

Dogbert, I hope this wasn't too much of a thread jack.

[Greebe]

Q refers to system Quality. A Q of 0.7 produces the smoothest bass rolloff/extension with the least distortion, but the price paid for it is less bass in the upper regions where it's typically annunciated in Pop/Rock (say ~50 - 150Hz). To the listener it would make the bass appear thin instead of robust/punchy like it's intended to be heard.

[Dogbert]

KvH, I can't really have a listening test with any of those.
The subs we have here on sale a re Yamaha, Magnat, Wharfedale (Topaz series - they stink), Paradigm (the good ones are EXTREMELY expensive), B&W (same, very expensive), Cervin Vega (Need to say EXPENSIVE again) and maybe a few more.

[Greebe]

BTW an easy way to increase Q of any bass speaker is to reduce the internal volume of the baffle (cabinette). Many use bricks or styrene foam todo, adding a little at a time until desired effect is produced.

If it's ported as in a Bass reflex design (or bandpass) shortening the bass port length will improve the upper bass when done in conjunction with the reduction of internal volume.

Note: by doing this you will be sacrificing the extreme low end of the speaker to gain the extra effeciency in the upper ranges.

[xortam]

My fronts (KEF 107s) have controls for adjusting the Q and defaults to 0.5.

[Greebe]

Yes your KEF's do it electronically... not the same thing tho. They're changing the Q of the filters (read: quasy equalization), not the physical Q (read: mechanical) of the system.

[xortam]

... of course, but the effect should be quite close. I've never played much with the K-UBE settings on these speakers.

P.S. BTW, the manual describes the effect as:

"A higher Q-Factor will increase overhang or "boom" and a lower factor will produce less overhang, sounding drier or lighter."

[Laurie]

I noticed in the Rava review it is stated that 'because it is not magnetically shielded do not put it near the tv.' Does it not matter where the subwoofer is placed?

[xortam]

I believe conventional wisdom is to place your sub in a corner and firmly planted to the floor. I attached some heavy duty conical spikes under my sub to enable it to burrow through the carpet and make firm physical contact with the hardwood floors. Some prefer to have the sub placed on a concrete foundation.

[Greebe]

@xortam
It is not, nor will it ever be the same... hearing the difference between the two effects is quite noticable.

P.S. BTW, the manual describes the effect as:
quote: "A higher Q-Factor will increase overhang or "boom" and a lower factor will produce less overhang, sounding drier or lighter."

Which is basically as I stated above to less of a degree and is marginally incorrect (Q=0.7 is optimium not 0.5).

@Laurie
As long as the sub is placed in the forward section of the listening area it will sound more or less proper. Placing it in a corner can augment the bass considerably, but you will have to try different locations as it may impair the overall reproduction at the listening position due to standing waves.