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[Hilton]

Hi

I used to have all my speakers behind my acoustically transparent screen but today I started a project to convert my existing Sony SS-CNX70ED centre speaker to an in-wall speaker to go behind my spandex acoustically transparent projection screen. (the left/right will just come out to the side as per Pic.)

In-wall speaker conversion by Hilton, on Flickr

The seating distance was a little too tight for my liking so I wanted to move the screen back an extra 50cm (20") to give me just over 3M (10 Feet) seating distance for the 120" screen.

I figured it will match my main Sony SS-X70ED Speakers better than buying an aftermarket in-wall speaker.

In-wall speaker conversion by Hilton, on Flickr

In-wall speaker conversion by Hilton, on Flickr

I've been careful to match the original internal speaker enclosure volume as closely as possible with a custom performance enclosure for the wall that just happens to fit between the wall beams at exactly the right size and position I needed.

I'm also using a similar internal brace structure as the original enclosure and putting a 90deg bend in for the bass reflex port with a piece of 50mm PVC.
Fortunately 50mm PVC pipe happens to match the internal diameter of the original port.

This should replicate as closely as possible the original enclosure performance, though I expect quite a different sound with something like an extra 6db of boundary gain in the bass region.


In-wall speaker conversion by Hilton, on Flickr


I've also kept the original speaker alignment and geometry to keep the time and phase alignment of the original design.

In-wall speaker conversion by Hilton, on Flickr

Testing fitting in the wall before I assemble it.
I just have to turn the power off tomorrow to remove the power distribution box I found in the wall. It wasn't connected to anything but it is live. Lucky my stud finder alerted me to it's presence!

Tomorrow I'll finish it and let you know how well it works!

In-wall speaker conversion by Hilton, on Flickr

[Hilton]

A small update before I get stuck into finishing it tomorrow.

Bass Reflex Port
In-wall speaker build by Hilton, on Flickr

The front baffle (note cutout section above main drivers)
In-wall speaker build by Hilton, on Flickr

Speakers recessed to get the right time alignment.  (in reference to the tweeter)
In-wall speaker build by Hilton, on Flickr

As good as it gets for today.

In-wall speaker build by Hilton, on Flickr

[JimH]

Good looking feet.   

[jmone]

I was thinking the left toe looks shorter than the right one....

...nice work apart from that!

[Hilton]

Thanks..

The hard part will be tweaking the baffle step compensation on the crossover for the new infinite baffle design.   If it's not sounding boomy I might just tune it with DSP correction.

[jmone]

Love a good hack!  I paid my speaker mfr to make one for me (my centre had to be recessed to get behind the screen for exactly the same reason)

[RoderickGI]

Did you guys look at the Bose in-wall speakers? I hear they are pretty good.

Or is suggesting Bose, or spending money, sacrilege?

[Hilton]

Did you guys look at the Bose in-wall speakers? I hear they are pretty good.

Or is suggesting Bose, or spending money, sacrilege?

I wanted the same speaker timbre to match the existing mains. So another brand wasn't an option unless my own efforts to make an in-wall centre speaker failed.. However I'm pleased to say I have succeeded.


I'm having a break and updating with some more pics before I finish off later this evening.

I just have to cut the speaker post hole and mount the crossover and glue it all together and it's done.



Here's the router circle jig I made up

In-wall speaker build2 by Hilton, on Flickr



In-wall speaker build2 by Hilton, on Flickr



Almost done!

In-wall speaker build2 by Hilton, on Flickr



In-wall speaker build2 by Hilton, on Flickr



It turns out the beam above where you can see the cuts in the plaster was a structural beam, so I had to go down the other way. No problem though it's still at just above ear height when sitting and about a third up from the bottom of the screen.

I'll just patch the plaster up and I'll be painting the wall anyway.

In-wall speaker build2 by Hilton, on Flickr



A bit more spandex speaker cloth stapled to the back to hide the hole for the tweeter.



In-wall speaker build2 by Hilton, on Flickr



In-wall speaker build2 by Hilton, on Flickr



Now off to finish after this coffee!!

[Hilton]

Finito!  (and yes there's insulation in behind the tweeter to stop reflections in the cavity)

In-wall speaker finished! by Hilton, on Flickr

In-wall speaker finished! by Hilton, on Flickr


Lines up!

In-wall speaker finished! by Hilton, on Flickr

[jmone]

Finito?  Spoken like an Ozzie Tradie!  My wife would kill me if I said I was done at that stage    Well done on the project (so far) though.

[Hilton]

Finito?  Spoken like an Ozzie Tradie!  My wife would kill me if I said I was done at that stage    Well done on the project (so far) though.

Yeah Mate~     Yeah well the hard work is done. It sounds great! I'm cleaning up now. She's still away up the coast, but she did see the mess before we went away and said it had to be done before she gets back Saturday.
So patching and painting tomorrow.

[Hilton]

I listened to a few bits of music videos and movies for a last position check. (not that there's much I could do at this stage anyway)  All centre audio is positioned perfectly!

Now to put the screen up and finish tidying up till tomorrow's painting job.

In-wall speaker position check by Hilton, on Flickr

In-wall speaker position check by Hilton, on Flickr

[Hilton]

In-wall speaker back together! by Hilton, on Flickr

In-wall speaker back together! by Hilton, on Flickr

[lepa]

Nice project Hilton! Always interesting to read about your DIY's.

[Hilton]

Nice project Hilton! Always interesting to read about your DIY's.

Thanks Lepa!

It was definitely a worthwhile project.

The sound stage is definitely a little better with the speaker in the wall and the screen mounted against the wall compared to when I had all LCR speakers behind the screen and the screen about 70cm out from the wall. Even though the screen is acoustically transparent, it still caused some sound reflections when the speakers were all behind it with the screen out from the wall.  The sound stage is miles better though than having the speaker under the screen.

The sound is very well blended with the main L/R and a quick whitenoise test on my iphone with sigscope pro showed absolutely no humps or dips on the centre speaker. I'd say it's very well matched as is and may not need any infinite baffle tuning.  I will do so more thorough measurements and testing over the weekend and see what REW says about it.    I love it!!!  My next project of Google Home integration has started and I'm very happy with the results.. stay tuned.. I'll post about my experiences with Google Home.