• 01-25-2006, 02:40 PM
    kexodusc
    1 Attachment(s)
    Latest speaker project finished (pics)
    Finally finished the home theater system I've been working on since mid-December. These are going to a co-worker/friend of mine who's replacing his Energy Connoisseur C-7's and v.2 Paradigm PDR-12 sub and taking his first plunge into Home Theater.

    http://custom.smugmug.com/gallery/115064/7/53882427
    (the last 5 are the speakers in this particular project...note the young guy in the photo is about 6 ft tall).

    The 5 speakers all use the same tweeter and woofer...the ever-popular Dayton 5-1/4" Classic woofer and the legendary Dayton 1-1/8" Silk Dome tweeter (which fans of Morel will recognize as a clone of sorts of Morel's MDT-29 high end tweeter). This tweeter is a steal, and wouldn't be out of place with a woofer costing double what I spent here. Better than the Peerless tweeter in the Ar.com DIY design IMO.

    This design was (loosely) based on the Dayton Budget Project by "The Reverend" Wayne Jaeschke...gotta give credit where credit is due. Obviously the drivers are the same, and the crossover topology was mostly preserved. The surrounds (there's 4) are all sealed enclosures of smaller volume, but with slightly less baffle step compensation since these are going to be wall mounted. The Center channel is a bit different shape and volume as well, ported, with again, different BSC to acount for its horizontal placement and the fact its baffle is effectively extended by the 57" TV it rests on.

    The towers of course have different internal volume, but I maintained Wayne's original xo design for 2 reasons: the baffle width was the same, and I ran out of any other capacitor and resistor values anyway.

    These have dual 8" subs mounted in them, separated from the speaker chamber by a double thick MDF wall. Acoustic foam damping material used throughout, I dunno why, but I couldn't get polyfill to sound right without stuffing the heck out of these...first time that's ever been an issue. The subs are heckuva lot better than I'd expect, with an F3 measure at 29 Hz and "LFE extension" down to about 23-24Hz.

    They sound quite good for home theater. Better than the PDR-12 in this setup. And equally good for most rock/blues/techno kinds of music. Anything above 35Hz or so I'd say is this woofers strength.
    This is the 3rd subwoofer I've made with this $20 woofer and $50 amp. Their perfect for small to medium sized rooms, I'd say 200 sq feet or less. Two of these have no problem hitting about 94 dB comfortably, a bit higher if you count peaks, which makes it great for people like my parents, or my friend and his condo. Once they get above that though they'll run out of excursion very fast, and you can hear sound quality deteriorate. Also got to watch power requirements. The PDR-12 could keep going...that's the price you pay for using an 8" woofer and not a ton of power. But we knew this going into it. We've already got a drop-in uprade in mind if he ever moves. His loudest listening volumes were about 88-90 dB when we measured on his old system, and 95% of the time below 80 dB, so we've got lots of room here. 70 dB is comfortably loud in his condo. One 8" sub would of course be further restricted, I wouldn't push average volume much past 90 dB (like mom and dad).

    Overall, sound quality wise, the towers are small step up in performance. Better throughout the midrange and highs, much better imaging and soundstaging. The C-7's do at times seem to have a bit punchier bass/mid-bass though, which is mitigated with when using the subs, but good to point out. Vocals and strings were noticeably improved though.

    This design is similar to Parts Express' BR-1 kit that I often recommend for $140. The differences are the superior midrange the smaller 5-1/4" woofer has over it's 6-1/2" cousin, and slightly better imaging and soundstage. The BR-1 is definitely more full range, and without a sub, I think would be a bit more "fun" to listen too. Of course the BR-1 comes with pre-fab cabinets for $140 though, so that makes it tough to beat for a lot of people.

    I put this speaker's overall presentation as slightly better than Axiom M3Ti's, or my old Paradigm Mini Monitors in terms of comparable performance. The silk tweeter is IMO much better than the titanium domes in the Paradigms and Axioms in my opinion, and is heard in the smooth, highs, and airiness this speaker presents. The midrange is a tad cleaner and more revealing. It doesn't keep up with my Studio 40's, though the highs are probably a bit better. Can't knock a $15 woofer for that, though.

    Total cost for this "7.2" speaker system was just under $700. The black ash vinyl laminate is comparable to what you see in stores, and is much quicker and easier than sanding, veneering, staining, sanding, varnishing, sanding, sanding, etc....Not to mention cheaper. I probably saved 5 hours of work with that choice.
  • 01-25-2006, 05:46 PM
    kexodusc
    Hmmm, seem to be having some issue with uploading the pictures...doh....
  • 02-01-2006, 08:41 AM
    MCH
    They look quite nice!
    ? Are the subwoofers integrated with the speaker crossover or are they totally independent and driven by their own sub amp.
    Personally I avoid having subwoofer drivers powered by the amp that drives the speakers. Subwoofers need a lot of power and most receivers cannot accomodate that power.
  • 02-08-2006, 08:33 AM
    kexodusc
    1 Attachment(s)
    The subs are of course powered by individual plate amps located on the back of the speakers in the lower "sub chamber" of the towers. I would have probably had to design a whole other crossover to tame impedance and common frequencies if I didn't...Not to mention the power issues you mentioned. You can sort of see the amps in this picture
  • 02-08-2006, 08:35 AM
    kexodusc
    1 Attachment(s)
    And...
    Here's a good shot of the cabinet interior, 2 hole-braces and a shelf divider that serves as a 3rd brace...you can see the dado joints, I love dados....way stronger and easier than butt joints.
  • 03-01-2006, 04:54 PM
    Geoffcin
    I don't know how I missed this thread
    Quote:

    Originally Posted by kexodusc
    Here's a good shot of the cabinet interior, 2 hole-braces and a shelf divider that serves as a 3rd brace...you can see the dado joints, I love dados....way stronger and easier than butt joints.

    But a belated "Great Job" is in order. I can't belive how well made these are at the absurdly low price for made them for. And with built in subs no less?! DefTech better watch out!
  • 03-02-2006, 06:28 AM
    kexodusc
    Forgot all about DefTech, but the powered towers is there thing, isn't it. The Black Ash vinyl makes these sort of DefTech knock-offs. Cool. I wonder if DefTech uses 3/4" MDF and crossover parts of 2% tolerance or better, selected and matched individually? (I'm guessing not at that price). I'll say one thing, after working with the vinyl laminate, I don't know if I'll ever bother with wood veer again. No sanding, staining, sanding, varnishing, sanding, varnishing, etc...Not to mention 1/4 the cost. Hey, we live in a plastic world, why not.

    Observation: It's amazing how much of these speakers are made of polyurethane in one form or another.

    I can't believe how good these sound for the price. My only regret is they aren't mine. Towers weigh a good 90lbs each. I tried convincing my friend to go with a separate subwoofer, 12" or something, but he wanted to save floor space.. I think performance might have benefited a bit more from that but the dual 8" woofers in the very large cabinets was a pretty good compromise. In hindsight, I shouldn't have been surprised, a 12" is about the equivalent cone area of two 8" woofers. The low tuning captures most of the bottom end, and the excursion demands are kept low by virtue of two woofers.

    70 watt amps too, good ol' Class AB not those goofy peak Glass G or Q amps. I really think today these high watt amps are more for bragging rights in most cases. My 240 watt amp 15" sub smokes my old 1200 "peak" watt PW-2200.
  • 03-02-2006, 06:52 AM
    GMichael
    Hey, I missed this one too!

    Great job Kex. They look nice. Bet they sound good too.
    Has your friend heard them yet?
  • 03-02-2006, 08:15 AM
    L.J.
    Dang Kex!! You got some SKILLZ!!!! I shoulda paid more attention in woodshop. Ever think about pullin a profit? :D
  • 03-02-2006, 08:43 AM
    kexodusc
    Quote:

    Originally Posted by GMichael
    Hey, I missed this one too!

    Great job Kex. They look nice. Bet they sound good too.
    Has your friend heard them yet?

    Yeah he took them a few days after I made them, I only had them for a week and could only run 2 channels at a time. The pics are actually done by him, I think I'm the only person in the world who still doesn't own a digital camera.

    The full HT demo's occured at place. He's got himself a very nice sounding system now well tailored to his needs and room size. Man I wish I knew this stuff before I was giving PSB and Paradigm all my money.
  • 03-02-2006, 09:39 AM
    GMichael
    I still have 4 home made speakers in my basement that I made from cheap drives. They sound pretty good but I wanted to treat myself to a set of "real" speakers and went out and got the Infinity's last year. These are the first whole speakers I have purchased in 30 years. I've been assembling my own sinse the mid 70's. Looking back, maybe I should have just kept building my own. Just should use better drives.

    Again, great job.
  • 03-02-2006, 09:49 AM
    kexodusc
    Quote:

    Originally Posted by L.J.
    Dang Kex!! You got some SKILLZ!!!! I shoulda paid more attention in woodshop. Ever think about pullin a profit? :D

    I have a full-time job, finding hobby time is hard enough.
    I'm just a hack who's learned a few things from some books and some really smart people on friendly web-forums devoted to the hobby. Can't see me ever doing it for money, though I have been building sub cabinets for a lot of teenagers for 2nd hand car-audio equipment lately. :D
  • 03-02-2006, 10:17 AM
    kexodusc
    Quote:

    Originally Posted by GMichael
    I still have 4 home made speakers in my basement that I made from cheap drives. They sound pretty good but I wanted to treat myself to a set of "real" speakers and went out and got the Infinity's last year. These are the first whole speakers I have purchased in 30 years. I've been assembling my own sinse the mid 70's. Looking back, maybe I should have just kept building my own. Just should use better drives.

    Again, great job.

    Great drivers aren't a must, a good crossover is. Software has really made taken out a ton of the guesswork in that aspect. You can model a crossover without any measurment equipment at all today and predict with good accuracy what real world performance would be. Through in a cheap microphone, tone generator, spectrum analyzer, multimeter etc, and you're laughing.
    As I understand it, the whole DIY thing has really boomed since the internet came along, drivers are better and cheaper. Best part is with all the free designs available now, the guesswork is out of it. Not everyone has time for this stuff. But I always like puttering around woodworking anyway, and have been buying and fixing used amps for a few years now, it fit me perfectly.
  • 03-02-2006, 10:56 AM
    GMichael
    Quote:

    Originally Posted by kexodusc
    Great drivers aren't a must, a good crossover is. Software has really made taken out a ton of the guesswork in that aspect. You can model a crossover without any measurment equipment at all today and predict with good accuracy what real world performance would be. Through in a cheap microphone, tone generator, spectrum analyzer, multimeter etc, and you're laughing.
    As I understand it, the whole DIY thing has really boomed since the internet came along, drivers are better and cheaper. Best part is with all the free designs available now, the guesswork is out of it. Not everyone has time for this stuff. But I always like puttering around woodworking anyway, and have been buying and fixing used amps for a few years now, it fit me perfectly.

    True I guess. But the last set I made, I used auto drivers. The crossovers are these: http://www.partsexpress.com/pe/showd...number=260-230


    Tweeters: http://www.audio-warehouse.com/web/mdl/LT18/detail.asp
    mid: http://www.audio-warehouse.com/web/mdl/LM57/detail.asp
    sub base: http://www.audio-warehouse.com/web/m...29X/detail.asp

    I didn't think to put in plate amps to drive the base. I was still old school (what's a powered sub?) at the time.

    How do you finish yours? I've always sanded & painted.
  • 03-02-2006, 03:32 PM
    kexodusc
    Usually I veneer my speaker cabinets. For car audio stuff I just buy carpet for car audio. My last few projects I've used vinyl laminate...the false wood grain stuff 99% of speakers under $1500 have. Much easier and quicker IMO. It looks ok, but not as nice as real wood veneer.

    I have a few sheets of nice baltic birch ply, but the stuff's so expensive I'm afraid I'll destroy it. Think I'll try some cheaper birch ply in my project as a practice run.

    The PE crossovers are decent stock crossovers. You'd get much, much better results with a customized crossover. The stock xo's are textbook electrical filters. Problem is every driver doesn't behave like a true 8 ohm resistor assumed in the crossover, it varies across frequencies. So the stock textbook values rarely have the desired effect. Often it's off by a fair margin. Especially in the midrange.
    Usually you try to accomplish an acoustic filter, that would be the "real" 6 db/octave, 12 db/octave etc, slope you want based on the two drivers' profiles. Then you might need to "pad" a tweeter to match it's volume to the other driver. You might need to equalize the impedance of the circuit too so the amp doesn't see too low of a load across a certain pass band. That mucks stup up further.
    Then you can try mixed order slopes, series crossovers, incorporate baffle step compensation, and 200 other cool little circuits to shape the systems response. Crossover design is really an art as much as a science. I'm very much a newbie at that still. Usually I can look at what other people have done in designs with the drivers I'm using, borrow ideas, and put something together. Then tweak it. I've only made one completely original crossover myself so far and that took me about 60 days of experimenting.
    All good fun though.
  • 03-02-2006, 05:55 PM
    Geoffcin
    Ok big shot, see of you can pull this one off. ;)
    Quote:

    Originally Posted by kexodusc
    Usually I veneer my speaker cabinets. For car audio stuff I just buy carpet for car audio. My last few projects I've used vinyl laminate...the false wood grain stuff 99% of speakers under $1500 have. Much easier and quicker IMO. It looks ok, but not as nice as real wood veneer.

    I have a few sheets of nice baltic birch ply, but the stuff's so expensive I'm afraid I'll destroy it. Think I'll try some cheaper birch ply in my project as a practice run.

    The PE crossovers are decent stock crossovers. You'd get much, much better results with a customized crossover. The stock xo's are textbook electrical filters. Problem is every driver doesn't behave like a true 8 ohm resistor assumed in the crossover, it varies across frequencies. So the stock textbook values rarely have the desired effect. Often it's off by a fair margin. Especially in the midrange.
    Usually you try to accomplish an acoustic filter, that would be the "real" 6 db/octave, 12 db/octave etc, slope you want based on the two drivers' profiles. Then you might need to "pad" a tweeter to match it's volume to the other driver. You might need to equalize the impedance of the circuit too so the amp doesn't see too low of a load across a certain pass band. That mucks stup up further.
    Then you can try mixed order slopes, series crossovers, incorporate baffle step compensation, and 200 other cool little circuits to shape the systems response. Crossover design is really an art as much as a science. I'm very much a newbie at that still. Usually I can look at what other people have done in designs with the drivers I'm using, borrow ideas, and put something together. Then tweak it. I've only made one completely original crossover myself so far and that took me about 60 days of experimenting.
    All good fun though.

    How about designing a set of nearfield monitors for use with a computer?

    The CSW M50's that I was using were confiscated by my daughter, so I'm back to square one on my search for an ass-kicking set of monitors for my computer system. I've looked online and I can't find a single DIY project for a pair of small nearfield monitors. Help me out here man!
  • 03-02-2006, 06:37 PM
    kexodusc
    I've never done "nearfield" monitors. Not really. I've done a 1 driver, full range, 3" speaker with a filter network that I'm thinking of doing again for my computer...but that's just a cheap $19 per speaker project. Sounds good enough, but it's more like the DIY version of an HTIB. Except they sound better than an HTIB. I don't know your budget but Paul O'Neal has designed a few speakers for nearfield listening now that look very impressive and have earned praise from the PE tech talk board (tough crowd).
    He posts here now and then under "poneal".
    His site is:
    http://home.stx.rr.com/poneal/index.html?Page=Speakers

    Alternatively, you can buy an absolutely excellent kit from NorthCreek Musisc Systems called the Echo! It has a wicked sounding, speaker in a small package. I use the nice silk tweeter in a few other projects. $36 for matching tweeters is a great dealt.
    http://northcreekmusic.com/Echo/EchoInfo.htm
    These guys know their stuff. The Echo won't have as much bass, but otherwise I think wouldn't be out of place beside the Totem Rainmaker - which is exactly what I thought of when I first heard this kit. Close to a wall with the midbass hump, they sound bassier than they are.

    Throw in one of those 8", 70 watt subs for $100 for all materials and you're set.