# New AV cabinet



## Howard Ferstler (Sep 27, 2007)

I previously pictured and discussed an audio equipment cabinet that I built. That article can be found on this site at:

http://www.woodworkingtalk.com/f13/new-audio-cabinet-29291/

Since that series of photos were taken, the room has been completely redone, with the paneling gone (plaster walls now) and new carpeting and new bookcases installed. Drapes replaced, too.

Pictures of the revamped room, along with an article by me on a pair of super subwoofers I built for that room, can be found at:

http://www.woodworkingtalk.com/f13/different-kind-audio-subwoofer-31884/

But I digress.

This time, I wanted another cabinet for my AV system in another part of the house. The one in there was an old vinyl-covered thing we (my wife and I) had owned for years, and we wanted it to be replaced. (It is now at Goodwill.)

So, we have this new cabinet. Unlike the one I built before, which had a cedar top, bottom, and sides, with mdf shelves, this one has Cedar only on the top and bottom (like the other cabinet, it is 1.5-inches thick), with double-thick mdf (also 1.5 inches) for the sides and standard-thickness mdf for the shelves. The cedar for both cabinets was purchased in rough-cut form from Home Depot, and so I used both a thickness planer and jointer to get the wood planks where I wanted them. Both screws and glue were used during assembly, with Kreg pocket cuts used in some places.

The mdf sides use single sheets on the outside, with spaced segments on the interiosr (glued and screwed to the outer panels), with those spaces serving as dado-styled grooves for the shelves to fit into. Unlike the previously built cabinet, which had the dado-cut grooves in the cedar sides open ended at front, this new one has cedar trim strips down the vertical front edges to hide the ends of the cuts.

The earlier cabinet was made of darker cedar (it comes in a variety of shades, as most of you know), and so I simply clear coated it and it came out very well. This cabinet’s cedar was much lighter, so I did apply some red-oak stain and then clear coated it. The sides were given a clear lacquer coating and the shelves are coated with very dark brown lacquer.

The cabinet is somewhat taller than the first one, because it has more stuff in it. It is also considerably heavier. (Mdf is heavier than cedar.) The small TV on top is used to program the video recorder on the first shelf. Under that shelf is a BluRay player, under that is a big Yamaha receiver, and under that is a Rane THX-44 equalize for the three front channels and the subwooferr. The bottom shelf has an AudioControl one-third-octave real-time analyzer that is simply stored there, unplugged. It does get use when I am equalizing both of my installations for smooth response.

Howard Ferstler


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## aardvark (Sep 29, 2011)

Nice Howard.
You know your gonna catch heck for no before/after photos.
I like your tastes in audio and accessories. 
Oh, the little tv is comical sitting on top, even though I get it's use., but a nice touch...Ha!


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## woodnthings (Jan 24, 2009)

*beautiful!*

The red color on the Cedar and the black really go together nicely....who would have thought Cedar? :thumbsup: bill


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## Howard Ferstler (Sep 27, 2007)

aardvark said:


> Nice Howard.
> You know your gonna catch heck for no before/after photos.
> I like your tastes in audio and accessories.
> Oh, the little tv is comical sitting on top, even though I get it's use., but a nice touch...Ha!


The original cabinet was, well, ugly. It would be out of place on this site. The small TV is a decade old (maybe older), and black and white on top of that. Serves as a menu screen for the recorder just fine, however. The main set in the room is a 56 incher and I just do not like to crank up something like that to program the recorder. (In the old days, you could program a recorder from its front-panel readouts, but no more.) 

I will attach a shot of the front wall of the AV room, showing the three satellite speakers I made (I have an entry on this site describing their construction), plus a big Hsu subwoofer that handles the low stuff. Good system. Not quite as potent as my main music system (which has no video), but still pretty good.

The receiver, by the way, is a Yamaha RX-Z1. Somewhat old, but still potent.

Howard Ferstler


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## Howard Ferstler (Sep 27, 2007)

woodnthings said:


> The red color on the Cedar and the black really go together nicely....who would have thought Cedar? :thumbsup: bill


The weak point with cedar is that it is soft. But, if you leave it alone (probably not the best wood to use if you have kids, which we do not) it can look really nice.

Howard Ferstler


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## aardvark (Sep 29, 2011)

But then if cedar is sealed hard, it's durable. I just did a hollow log surface which is maple which is semi soft, but with 10 coats of poly, it will take a lot to dent it.
What's in the Sat spkr's?

I still love the old lil tv. It's like an antique on display and I remember those being able to be run on 12v car power for camping. It' a keeper and accentuating it would be a blast for fun, as well as running it at the same time as the big screen is on for a novel effect.
My dad was in radar in the service and had the first 1950's cabinet tv's with a screen not much bigger than that,,,in a full sized cabinet.

I was running a Harmon Kardon AVR20, surround receiver which I loved and outpowered my ole Marantz 2270 stereo. It finally got the audible buzz disease, and after dissecting it, and replacing power supply cap's , I had no success. It now sits aside and I picked up another HK, model 210, which I like a lot. It's moderately powered but is stable on the low freq's. Far from high end, but at moderate listening levels (and above that gets the wife agitated) , it works well. The ole units didn't even have a remote.
Old is not necessarily bad, and I grew up around tube amps like modified/tweaked Heathkits.

Love the cabinet and coloring. Great design yet basic.


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## Nandor (Dec 10, 2011)

i would like to know more how did you stained the cedar.i always thought cedar can not be stained because of the toxic gases that release.


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## Howard Ferstler (Sep 27, 2007)

aardvark said:


> But then if cedar is sealed hard, it's durable. I just did a hollow log surface which is maple which is semi soft, but with 10 coats of poly, it will take a lot to dent it.
> What's in the Sat spkr's?
> 
> I still love the old lil tv. It's like an antique on display and I remember those being able to be run on 12v car power for camping. It' a keeper and accentuating it would be a blast for fun, as well as running it at the same time as the big screen is on for a novel effect.
> ...


Hey, 

Hopefully, the three coats (two brushed on, the final one sprayed on) of Minwax semi-gloss urethane will decently protect the surface.

The drivers in each of the main units (left and right channel) include a pair of Allison convex-dome tweeters and a pair of Tang Band 4-inch cone drivers. The groups are set up in vertical MTTM arrays. At the bottom of each cabinet is a single 6.5-inch Allison woofer. The crossover from the satellites to the sub is at 90 Hz, so the small woofers are not put under stress. 

The center speaker is much the same, but with three-inch Tang Band mids. (The top and bottom sections of each enclosure are separate, to keep the woofer backfeed from impacting the cone midranges.) The crossover points for the bigger units are at 300 and 4000 Hz. With the smaller one, the lower crossover is at 400 Hz to better protect the smaller mids. Attached are photos of each type.

I discussed the design and building of the systems on other parts of this project site. Check this for some info on how the center unit was constructed.

http://www.woodworkingtalk.com/f13/serious-center-channel-speaker-15389/

Howard Ferstler


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## Howard Ferstler (Sep 27, 2007)

Nandor said:


> i would like to know more how did you stained the cedar.i always thought cedar can not be stained because of the toxic gases that release.


Hmmm. Interesting. This was my first attempt at staining the stuff. I let the Minwax sit for only a minute (they recommend 5 to 15) and after about 12 hours I applied three coats of urethane. If any gasses were released (my workshop is out back, separate from the house, so gas emissions were no problem) they would not have been an issue, and I assume the urethane has sealed the surfaces since then.

Howard Ferstler


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## aardvark (Sep 29, 2011)

No, a 90hz crossover shouldn't effect a 6.5" woof , normally.
Thanks for the link.
Now i have some evening reading to do.


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## aardvark (Sep 29, 2011)

Well, that didn't take long.
I did notice 2 things of interest in your building process. 

One is the differing woods for resonance control. Good point. MDF overall on it's own is dense enough to do it, but generally standard tree boards are not good on their own. The use of 2 or more woods helps that drastically, especially with MDF. Generally I use 3/4 MDF. Gets a bit heavy to move...but so what.

The other was the isolation, via a blocking board between the bass a mid/hi sections to eliminate pressures from the sub pressure effecting the mids.(the hi's are generally sealed...no issues). It is a practice I use as well. Separate cavities in the same box, and the box area cu. ft. designed to the speaker attributes..

Thanks for the read.


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## Howard Ferstler (Sep 27, 2007)

aardvark said:


> Well, that didn't take long.
> I did notice 2 things of interest in your building process.
> 
> One is the differing woods for resonance control. Good point. MDF overall on it's own is dense enough to do it, but generally standard tree boards are not good on their own. The use of 2 or more woods helps that drastically, especially with MDF. Generally I use 3/4 MDF. Gets a bit heavy to move...but so what.
> ...


Glad I could offer up some evening reading entertainment for you.

Actually, the woofer cavities at the bottom are about the same internal size as those for the small, budget-oriented Allison AL-110 speaker produced by that company years ago. (Roy Allison, a good friend of mine, is now retired and his company is gone, but he designed some notable speakers both at that company and when he was honcho at AR after Edgar Villchur retired back in 1967.) Consequently, the woofer (which was used in that system, too) is quite at home there. The filling is fiberglass, with a smooth response down to about 65 Hz if the subwoofer crossover were not in operation. 

I had toyed with using two woofers (one above the other) in each cabinet, but the internal volume would not allow that to be effective unless I built bigger cabinets, which I did not care to do. My worries about woofer overload were not justified, because the small woofers have no problem at all with even the most potent action movies. The upper cabinet filling is polyester and not fiberglass.

Attached are two more photos. One shows the backside of one of the left and right speakers. Note that there are actually two crossover sections: a low-pass woofer section at the bottom and a high-pass section (for the tweeter) and bandwidth-limiting section (for the midrange) at the top. They are connected externally by a jumper wire. I used separat boards, because it reduced crowding inside of the narrow cabinets. (The speakers could also be biamped if I decided to do something like that.) The second photo shows the networks used in the center speaker, which are similar to those in the left and right units. Note that I did not use a printed-circuit plate for the components.

I have a much larger system in another part of the house (for music only), with big Allison speakers for the left and right channels and a home-built speaker for the center. The center unit has cedar wood (1.5-inches thick) for the top, bottom, and sides, with mdf for the front and back. It uses Allison drivers that match those in the big allison models flanking it (five each, with ten each in the big jobs), and to handle the bottom end I built two large subwoofers. You can see the center unit in an article (and photos) I did on the subwoofer project at:

http://www.woodworkingtalk.com/f13/different-kind-audio-subwoofer-31884/

The subs shake the room at 18 Hz, and were built with technical input from Poh Hsu (of Hsu Research) and Ed Mullen (of SVS). Nice guys, those.

Howard Ferstler


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## aardvark (Sep 29, 2011)

Yeah I've used polyfill for sound insulation and like it. since it holds together better. Especially under vibration.

I also split the crossovers into sections like you have done, but I've used offerings from Parts Express and was locked to their parameters, which were within what I was after for the speaker choices anyways. Looks like you assembled yours. You're running un-fused 

I have a few test CD. with sound tests like white/pink noises, warbling and specific frequency tones (to name a few). Not running a sig generator for my testing. 
Likewise my towers under amp power do well as do the unpowered subs. Everything I run is not powered by a separate amp. Just the HK unit. The 12" meet yours on low end freq, and the smaller subs in 10" get down near there as well, but not quite. It's been some time since I've tallied results, and cannot find them.


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## Howard Ferstler (Sep 27, 2007)

aardvark said:


> Yeah I've used polyfill for sound insulation and like it. since it holds together better. Especially under vibration.
> 
> I also split the crossovers into sections like you have done, but I've used offerings from Parts Express and was locked to their parameters, which were within what I was after for the speaker choices anyways. Looks like you assembled yours. You're running un-fused
> 
> ...


Actually, I am running fused. If you look closely you will see three polyfuses in the two networks. (Little yellow discs.) Those will gradually reduce the juice going to the drivers above a certain point, and will self reset. 

Roy Allison once told me that fiberglass is a tad better than polyfill, but in some cases the improvement is nil. I used it in the woofer section to maximize the acoustic volume.

The test CD I usually use is the Delos "Surround Spectacular" set, which has both test signals and some Dolby Surround encoded music. It was put together by John Eargle and David Ranada years ago. It has pink noise for the left, center, right, and "surround" (matrixed surround) channels, as well as an uncorrelated (stereo) pink-noise feed for both left and right channels together. The uncorrelated version does a better job of preventing false readouts in the low bass range when doing RTA evaluations of both channels together. With correlated dual-channel feeds the bass range is falsely elevated.

A copy of the schematic for one of my home-built left or right channel systems is attached.

Howard Ferstler


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## aardvark (Sep 29, 2011)

accoustically fiberglass might be better, but in longevity it tends to come apart to a minor degree with air movement. Polyfill won't dislodge from itself.
I can't see that the difference would be vast, and actually would think it would be minor.

Thanks for the schematic. I'll now have to pull out my books and see how they all wring out. It's like doing homework again.

(and I still like that small tv...Ha!)


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