RW12 meant for flush in wall mounting, with front port??

[DrWho]

Before you get totally settled in your new hole, I might suggest that you check out this link:

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=718

Ideally, you want to build a soffit inside your wall that is mounted to another set of studs not physically connected to your main listening room. The basic reason for this is that you don't want the cabinet to vibrate the wall because the wall will act like a huge baffold, muddying up your sound. But if you can't build the soffit thingy, this link still provides info for dampening the hole in your wall.

I noticed that you have to be logged in to see the pictures in the link, so I've decided to post them here for your reference (in case you're not wanting to register with the forum).

Another thing to keep in mind is that mounting flush to a wall drastically changes the frequency response of your speaker...basically, the low frequencies get louder. The following is a picture that demonstrates what this will look like:

The red line is your original "flat" response and the blue line is the new response when the speaker front is lined up with the wall.

And lastly, I might recommend that you bring the speaker so that the front of it just sticks out of the wall, rather than trying to stay totally flush. The driver sits behind the grille and you will get a boxy sound if the driver is at all behind the plane of the wall. bringing the grille out half an inch usually doesn't look bad and i doubt it'll get bumped either.

[Guest Deon Bearden]

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On 6/10/2004 12:15:16 AM gibby214 wrote:

Does anyone have any knowledge on placement of a sub flush with the wall. I have not seen or heard of it. The

RW12

is front ported and single front firing driver so I would assume the energy would all go forward out.

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The RW line of subwoofers while not specifically designed for the contractor 'install' market, was indeed designed to be 'install friendly'. Provided the location of the woofer sounds good to you, the wall doesn't vibrate noticeably while playing, etc, running it in the cubby hole you have it in should pose no operational problems.

Nice install btw

[Guest Deon Bearden]

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On 6/10/2004 8:49:01 AM gibby214 wrote:

I would say right, left and top of the sub has about 3/8 of an inch around it, About enough to turn my volume with a pencil eraser and a flash light. The rear has about 4 inches clearance for wiring. All of it could easily be foamed or filled in. Is this floating sub correct or should it be firmly anchored to the floor. The bottom of the box is about 3.5 inches off of the floor if this makes any difference. Thank you for any help here.

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There space you've left around the woofer is plenty. No need to fill the area with foam. Hight off the floor will have little impact, remember that one wavelength at 80hz is roughly 14 feet long, one wavelength at 20hz roughly 56 feet long. 3.5" from the floor is fine.

[Guest Deon Bearden]

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On 6/22/2004 12:28:34 AM gibby214 wrote:

My yamaha rxv1400 reciever has in the menu some low freq test tones. ~ The sound can be sent to any of the ~ speakers. ~ Would this also be a tool to use for phase?

Is there calibration discs for audio like there is for high def video like the avia dvd disc. I don't own one yet but maybe avia has audio on it.

gib

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A quick down and dirty method to calibrate your phase. Apply a test signal to both mains and subwoofer at the approximate crossover freq of your sub, example 60hz (if that's where yours is set). Place mic at listening location, or your use your own ears..

Vary phase while playing the signal through both the mains and sub at the same time with the polarity of the MAIN speakers INVERTED with respect to their normal hookup (Negative to positive).

Vary the subwoofer phase till you get the LOWEST output at the turnover freq. Go back to mains, and return their polarity to normal (neg to neg, pos to pos) Viola, your main speakers and subwoofer phase are now pretty doggon close to matched. To get the polarity much closer you'll need sophisticated measurement gear and signal generators.

Yes Avia has bass tone frequencies, and there are NUMEROUS other 'test discs' available online. If your receiver will send signals to more than one speaker at a time, then it may be useful in your case also.

Good luck.

[gibby214]

Thanks Dr Who and Deon.

I didn't know whether to get into the soffit (flush wall mounting) thing in this sub forum, but I am interested to hear any other experiences with it. On planning my install I had only two things in mind 1. Child Proof 2. Sleek Look. I just figured the 3 front ported RB75's and RW12 would give my idea brilliant sound. After reading this article from genelec http://www.genelec.com/support/soffit.php I was freaked out and excited both. Half spaces and Spherical radiation it changes the loading of the drivers. Diffractions are eliminated. Many pro's and con's to it. It's all new to me. My question is what frequencies should I be concerned about equalizing? I understand there is a bass boost, is that because of the half space, wall as a baffold.

gib

[doudou]

don t forget that an amp becomes hot when it works, so if your sub has not enought air to be cooled he could last less longer or blow.

[colterphoto1]

Nice room Gib!

Here's a hint on sub placement that you may want to experiment with before you decide on your final sub box installation. Think of the space around the sub as a 360 degree 'sphere'. If the box were floating in mid air in the middle of the room, the omnidirectional bass sounds would try to travel equally in all directions. By placing the sub on the floor, it is now radiating into only one-half of the sphere, against the floor and one wall, it's now basically in a rudimentary 'horn' radiating into one-quarter sphere, and the most bass is realized with the sub on the floor and in the corner between two walls or one-eighth of our sphere.

This is why placement is so important. Depending on the sub and the room dimensions, different frequencies will be pronounced. You can determine this with your ears, or test tones and a db meter (see Radio Shack for a basic one)

Even though you are putting your cabinet 'in' the wall, the same principles will apply, so you could use various temporary stands to experiment with prior to final placement. I agree with the installation tips given regarding isolating your sub mount from the wall. The last thing you want to create is a massive vibrating wall. Talk about coloration!

(this written with apologies to Artto, our resident acoustician, I'm just a simple man, but hope I got this right)

Michael