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Thread: Speaker Building Time Again

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    Default Speaker Building Time Again

    I thought some of you might be curious to see what I'm getting myself up to this week. About a month ago, I decided it was high time to upgrade the home theater. The last upgrade was back in 2002, when I bought this used receiver:



    Kenwood VR257. About the only thing special it has going for it is a 6 channel discrete input and a TV audio tuner. It's not that bad for an old Pro Logic, but way too old for me these days.



    This is the new one - a Pioneer VSX919. This is a 7.1 channel receiver with most of the latest bells and whistles you can get for $500 or less. But, I'm left unsatisfied. You see, I'm still using the old old old speakers I built way back when I was 14, with whatever I could find for center and surrounds:



    This here was the first speaker I ever built. I got a lot of flak from my Grade 8 shop teacher for this - he didn't understand what I was going for by putting one of these in the back panel:



    Radio Shack 15" woofer. This was the biggest, baddest thing I could get my hands on in 1987. 1.25" voice coil, 125W power handling. I wanted it in the back panel so I could corner load it. But terms like horn loading into a room corner and bipole configuration escaped my shop teacher, and he was pretty mean about it.

    Because I was only 14 at the time, I built this one too flimsily. It uses 1/2" plywood, and the whole enclosure vibrates when you crank it. I had to fasten down the wires inside to keep it from sounding like a machine gun. When I was 17, I built the companion for it using reinforced 3/4" stock - that came out a lot better. Good thing I didn't wait too long - those woofers went bye-bye at Radio Shack not too long after. Midranges were from MCM electronics, and the tweeters are Motorola piezo models.

    FWIW, I used these in a gymnasium at my friend's wedding. They filled the room easily. I actually ran out of amp power that day... I've run these on 300W each without issue.

    But, that was then and this is now. A pair of speakers I designed in 1987 are ill suited for home theater use. The above woofer actually blew its own dust cap off once - I had to glue it back down. So, I got started on the new ones yesterday. I'll start a new post for that.
    Last edited by Oklahoma Wolf; 07-12-2009 at 10:54 AM.

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    Building a 7.1 channel set of home theater speakers is a huge job. I bought this specifically for the job, because I knew I'd regret it if I tried to freehand cut panels for eight speakers.



    On sale for $65 with laser. A crosscut plywood blade is mandatory for this kind of thing. I also got a straightedge you can clamp to the wood, another essential tool if you don't have a table saw.



    I got just over half of the panels cut for the 7 satellites yesterday. Here they are. The subwoofer is still in the planning stages... I'm waiting for Mach 5 to restock their 18" IXL's. Will build that one using 1" thick stuff. Until then, my old 15" equipped main speakers will be pressed into subwoofer duty using a 200W JVC stereo receiver someone gave me to fix up.



    These will be the guts of the seven satellites. These are 5.25" Chrysler/Infinity coaxials with EMIT tweeters. Don't laugh - those tweeters are profoundly underestimated. The woofers aren't so good as they use 1/2" voice coils and tiny magnets, but I'm on a budget here and all fourteen you see in the picture cost me $35 combined.

    Each speaker gets two of these for 8 ohm operation. The Pioneer is rated at 90W x7, and these speakers are normally run at 40W each, so that should keep these from blowing, too.

    When I can afford better, I'll design new ones around Vifa or Audax components. Meantime, that Pioneer has 9 band EQ'ing for all channels - it will be put to use.



    Close-up of the EMIT tweeter. These are ribbon tweeters that have insane high frequency extension to them. They are VERY accurate, which is what I want. I can live with bad midrange for a while.

    That's all for now - will have more pics later when I go back out and cut the remaining satellite panels and eventually start putting these together.

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    Here I am at the end of day 2. Lots more hard work got done today, and I only stopped because the drill battery went dead and my #6 screws threatened to run out.

    Finished up the rest of the panel cutting and got 4 of the 7 enclosures done. The final 3 along with all the hole cutting, wiring, and speaker mounting will all get done on Tuesday.



    This started out as a full 4x8' sheet of plywood this afternoon. It's 15mm thick like the other half sheet I chopped up yesterday.



    The end result of today's work. Not perfect, but I'm pleased with the way these came out. Much better than my past efforts with only a jigsaw to cut with. These will not be finished, unless I decide to rattle can them black. I don't mind the bare plywood look.



    The pile of unassembled panels is getting smaller, along with my stash of Mountain Dew.

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    End of day 3 after being forced by Mother Nature to take a day off. The satellites are done. Started at 10AM this morning and wrapped things up at 9:30PM. It was still wet and rainy outside, so I had to play with the jigsaw inside.



    4 of the 7 enclosures before hole cutting and final assembly.



    These came from Hong Kong off eBay - I started out with 10 pairs and now I have 3.



    5 of them ready to take the drivers.



    Testing phase. This is the receiver I was going to use for subwoofer duties temporarily. Piece of junk JVC still won't switch inputs properly though even after replacing the multiplexer IC, so I'm going to have to dig out the old old Noresco that hisses like mad but otherwise has a ton of power (possibly more than this JVC does).



    14 Infinity EMIT tweeters... wow. Just looking at this image makes me wonder about my own sanity in doing this.

    I only had time to mount 4 of the 7 tonight (the surrounds). The final 3 will go up tomorrow, and then I'll find out what the Pioneer thinks of them. I already ran the two surround back speakers off it for a test though... those EMIT tweeters just rule. They are considerably better sounding than what I had before.

    Subwoofer design has been finalized. Will start a new thread on that one eventually as I am months away from getting that together.

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    Final post until I can get the room cleaned up enough for pictures. Everything's installed and wired. Took 300' of speaker wire and then some to get all seven wired, plus the two "subwoofers."

    The Pioneer doesn't seem to mind the load, though the fan runs more often than it did before. I may yet add a 140mm fan to help cool it, or I may not. Undecided on that yet.

    Here's the subwoofer setup:



    That's the Noresco amp I mentioned sitting up top beneath the EQ. If you're wondering what the deal is with the cardboard, well, that thing actually used to have a Dual turntable bolted to it. It was broken when I bought it (the whole thing was priced at just five bucks), and since the speaker connections are non standard anyway I took it off and cardboarded it, ghettoing some terminals on top there.

    Believe it or not, the Noresco is rated at 120W total. That's a rather conservative number. See that speaker on the right of the picture? That's a 55W RMS Akai with a 10" woofer. I almost blew it to kingdom come with one channel of the Noresco once... it's that powerful. FWIW, the Akai was my center speaker up until today. I had it hanging from the ceiling.

    Listening tests have shown me the Noresco is still able to bring the power. I ran the DTS trailer at the beginning of Panic Room and it had those 15's shaking the ceiling tiles. I may not need a new subwoofer now. But I'm going to build it anyway
    Last edited by Oklahoma Wolf; 08-17-2009 at 10:51 PM.

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    Holy crap! Coming along.

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    Heh - the neighbors will be the ones saying holy crap when the new subwoofer goes together. 18" Mach 5 IXL in a 400-500 liter coffin tuned to 12Hz powered by a 1000-1500W pro audio amp. I may be able to set off local seismographs with that bad boy.

    I gave the new speakers their first major assignment this evening. Terminator II running in Dolby Digital EX. I am very, very pleased with the sound quality of the new speakers, and the temporary subwoofers are more than adequate for good sound at decent volumes even if I wish the Noresco could push them harder. Even so, I don't think I had it maxed out - the heatsinks on the back were barely warm.

    I must have gotten my internal series speaker wiring right - the fan in the receiver didn't come on once. It's running cooler than it did on the old setup.

    All in all, I'm happy with my $150 or so home theater upgrade project. That subwoofer is going to cost me some cash, but that's pretty much unavoidable.
    Last edited by Oklahoma Wolf; 07-20-2009 at 12:23 AM.

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    Interesting. I always liked they way they sounded in my Grand Voyager back in tha day.

    Did you make crossovers for them? from the factory they had amplifiers on the speaker frame right?

    I have 3 sets of EMITs in my house right now. In fact I am listening to a set of them in some old (restored) RSIIIa's behind me as I type. That's why I was asking about the crossover - I tried to work a set into a set of DIY speakers with some SEAS 7 inch midbasses but was having trouble getting them to work well with a standard crossover. I ended up copying the high frequency crossover in the RSIIIa's trying to get them to work right. Ultimately though I couldn't get the EMITs to go low enough to match up with the 7" mid without meltdown. Since they were for HT use I switched them to a standard 1" dome. I ultimately ended up turning them into the ZaphAudio SR71's which sound really, really good for such a small speaker.

    The Key with the EMITs is to not let any clipping get to them, moreso than other tweeters. my big infinities have a 1.5 amp resetable circuit breaker inline with them along with a couple zener diodes to clamp any stray volts to 'ground' and are still easy to cook. The other result of this particular arrangement is that near clipping your amplifier might see a 0 ohm load before the breaker trips, particularly during the super distorted parts of the 'pretty hate machine' CD from NIN. I learned a lot about amplifier repair due to this combination - especially the dot matrix swipe in sanctified. Luckily these speakers were still under warranty during that 'learning' period and Infinity used to replace my tweeters no questions asked. Unfortunately, no such warranty existed for the Pioneer - so I got good at replacing outputs and drivers. Strangely since the warranty expired on the speakers (in like '91?) my tweeter run rate dropped considerably.

    Hmmm. Someone just dropped a baby in my lap. . . Gotta go

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    No crossovers but the capacitor and resistor on the tweeter they had from factory. The woofers do cry out for a low pass crossover on them to replace the one in the amp on the back, but the Pioneer's EQ seems to do ok in compensating.

    These Chrysler/Infinity versions of the EMIT don't seem to die often. I had one pair with an intermittent and dead EMIT, but I fixed them both easily by taking them apart and hitting the ribbon solder joints briefly with a hot 60W iron. Put them back together again, and they were perfect. They don't play very low though, as you found.

    I've had them fairly loud so far in the home theater - no dead tweeters yet. Then again with fourteen of them in one room, I'd expect them to be able to do some serious tweetering

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    Yeah - I suspect that 14 EMITs would tweet quite well. and 2 5.25s per enclosure should have a decent amount of punch, certainly enough to mate with your planned sub for any reasonable listening.

    Probably any unreasonable listening too. . .

    The video in your sig is cool - I have seen BT live a few times, mostly in his pre-hard drive getting stolen days, we used to get lots of good shows down here near Miami. I think one of the best shows I went to was BT in Ft. Lauderdale at some club that was like an abandoned mall (orbit - http://websitefirstaid.com/portfolio/orbit/index.html - long since shutdown). They had BT in the main room and 3 other rooms with crazy stuff going on. . . Lots of crazy stuff . . . I vaguely remember walking from the main room where a 15 minute version of Dreaming was ending and walking into a smaller room hearing a DJ spin a techno version of the verve's bittersweet symphony, then wandering into another room where another Dj was spinning PPK - Resurection (club space mix). I was in heaven.
    Last edited by CBRworm; 07-21-2009 at 11:39 AM.

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