Joe P Posted December 9, 2011 Share Posted December 9, 2011 I have two of these speakers that I swapped out of a Peavey bass cabinet for a bass player friend. There's nothing wrong with them and I was kicking around the idea of making some cabinets for them for home practice use. Right now I could power them with either a Peavey Classic guitar amp, a Peavey bass amp head, or a Peavey powered mixer PA head (I think - I'm not too good with electrics). My keyboards sound pretty good through the bass head and the original cabinet using the EQ on the bass head. So I'm wondering if it's possible to build two cabinets, one for each speaker and what geometry I should shoot for to get the best sound. I'm not looking for stellar audio, just something permamently set up that I can use instead of bringing my keyboard amp in and out. Regards, Joe Link to comment Share on other sites More sharing options...
Griffinator Posted December 9, 2011 Share Posted December 9, 2011 Yeah, there's a hell of a lot more that goes into building a cabinet than you want to know about. Trust me. Making a square and cutting a hole in it isn't the end all, and will likely leave you with something that sounds like ASS. A bunch of loud, obnoxious music I USED to make with friends. Link to comment Share on other sites More sharing options...
ITGITC Posted December 9, 2011 Share Posted December 9, 2011 Yeah, there's a hell of a lot more that goes into building a cabinet than you want to know about. Trust me. Making a square and cutting a hole in it isn't the end all, and will likely leave you with something that sounds like ASS. Agreed. "Music expresses that which cannot be put into words and that which cannot remain silent." - Victor Hugo Link to comment Share on other sites More sharing options...
Ken Beaumont Posted December 9, 2011 Share Posted December 9, 2011 You can buy empty cabinets cheap. I bought a pair of empty 12 cabs closed back of craiglist last year for $70. I had a couple of Carvin neodymium speakers I wasn't using. The cabs were seismic audio and the results were pretty good. I made them for friends teenage son to use with his bass. Boards: Kurzweil SP-6, Roland FA-08, VR-09, DeepMind 12 Modules: Korg Radias, Roland D-05, Bk7-m & Sonic Cell Link to comment Share on other sites More sharing options...
Griffinator Posted December 9, 2011 Share Posted December 9, 2011 You can buy empty cabinets cheap. I bought a pair of empty 12 cabs closed back of craiglist last year for $70. I had a couple of Carvin neodymium speakers I wasn't using. The cabs were seismic audio and the results were pretty good. I made them for friends teenage son to use with his bass. Would be a much smarter move than trying to build your own, for sure. A bunch of loud, obnoxious music I USED to make with friends. Link to comment Share on other sites More sharing options...
mate stubb Posted December 9, 2011 Share Posted December 9, 2011 But you have to match your cabinet to the speaker, at least if you want decent bass. This involves the right porting for the resonant frequency of the speaker, etc. And you are right back to knowing more than you care to. Anecdote: back when dinosaurs ruled the earth, we used to carry 4 klipsch folding W horn cubes for subs. They had cheap eminence speakers that kept blowing, so we tried JBLs. They sounded like crap, even though those same speakers sounded great in front loaded cabs. The flappy Eminences were loaded by the horn and actually sounded better. Moe --- Link to comment Share on other sites More sharing options...
Griffinator Posted December 9, 2011 Share Posted December 9, 2011 Agreed, MS, but it doesn't sound like he's super-concerned about the overall fidelity, just making it work decently. Buying prefab cabinets that don't necessarily match up perfectly with the given speaker would be a much better choice than trying to build his own, that's for sure. Regarding the Klipsch speaks: Sounds to me like you were loading way too much power for those poor little Eminences... Klipsch always designed their speaks to be as efficient as possible, to deliver massive volume with little power, but not necessarily to do more with more... Someone did basically the same thing to the Altec model 40's I picked up recently - put too much power to them and blew the active crossovers. I'm in the process of rehabbing them now, and very much looking forward to putting a little weenie 20 watt amp to them and filling the room with it. A bunch of loud, obnoxious music I USED to make with friends. Link to comment Share on other sites More sharing options...
mate stubb Posted December 9, 2011 Share Posted December 9, 2011 Sounds to me like you were loading way too much power for those poor little Eminences... Well it was 1973, so of course we were! Not only too much power, but it came from Phase Linear amps. When they failed, it tended to involve flames. Moe --- Link to comment Share on other sites More sharing options...
Joe P Posted December 9, 2011 Author Share Posted December 9, 2011 But you have to match your cabinet to the speaker, at least if you want decent bass. This involves the right porting for the resonant frequency of the speaker, etc. And you are right back to knowing more than you care to. Anecdote: back when dinosaurs ruled the earth, we used to carry 4 klipsch folding W horn cubes for subs. They had cheap eminence speakers that kept blowing, so we tried JBLs. They sounded like crap, even though those same speakers sounded great in front loaded cabs. The flappy Eminences were loaded by the horn and actually sounded better. Thanks Mate, I appreciate the reply. Regards, Joe Link to comment Share on other sites More sharing options...
Griffinator Posted December 9, 2011 Share Posted December 9, 2011 Yikes. I remember those amps... A bunch of loud, obnoxious music I USED to make with friends. Link to comment Share on other sites More sharing options...
Ken Beaumont Posted December 9, 2011 Share Posted December 9, 2011 Someone did basically the same thing to the Altec model 40's I picked up recently - put too much power to them and blew the active crossovers. I had a pair of Infinity Kappas that had the opposite problem. They were a huge power soak. I was having a volleyball party in Germany and had my stereo playing some tunes. The amp was a 350Watt per side Yamaha that could go all the way to 2 ohms and 800 watts. One of the guys from my unit turned the volume up all the way. In less than a minute no sound, blew a very expensive amp. No damage to the speaker at all. Another guy in my unit had the same speakers, blew his pioneer receiver in less than a month. Boards: Kurzweil SP-6, Roland FA-08, VR-09, DeepMind 12 Modules: Korg Radias, Roland D-05, Bk7-m & Sonic Cell Link to comment Share on other sites More sharing options...
Bill H. Posted December 9, 2011 Share Posted December 9, 2011 My keyboards sound pretty good through the bass head and the original cabinet using the EQ on the bass head. So I'm wondering if it's possible to build two cabinets, one for each speaker and what geometry I should shoot for to get the best sound. If you liked the sound of your keyboards through those speakers in their original cabinet, sure. Peavey Black Widows have continually changed (and a lot!) through the years. Your best bet for something decent sounding would be to copy the cab they came out of, and cutting the dimensions and vent size in half if you're building two. Getting it spot on wouldn't be critical for keyboards in a practice room (their intended purpose, right?) I've built my own cabs from time to time. My latest project was a pair of 21" subs that I put together here in my shop last spring - using a design off the speaker maker's website. One word of advice: Making a decent looking cab takes a lot of time. Link to comment Share on other sites More sharing options...
Musicale Posted December 9, 2011 Share Posted December 9, 2011 I've built a lot of cabinets over the years, designed and built crossovers etc. Its a lot of fun, you need to either have access to power tools or have wood cut to order and check out some designer website. I suggest looking at Madisound in Madison, WI. I think you'll want to add a tweeter along with these great Black Widows. That will give you a nice crisp sound to the higher frequencies. Good Luck, Musicale Link to comment Share on other sites More sharing options...
mate stubb Posted December 9, 2011 Share Posted December 9, 2011 ... but not a piezo tweeter. Moe --- Link to comment Share on other sites More sharing options...
Joe P Posted December 9, 2011 Author Share Posted December 9, 2011 Thanks all! Maybe I'll give it a whirl, after all I have nothing to lose. Regards, Joe Link to comment Share on other sites More sharing options...
ITGITC Posted December 9, 2011 Share Posted December 9, 2011 Thanks all! Maybe I'll give it a whirl, after all I have nothing to lose. Regards, Joe If I were to build a cab wih 15" Black Widows, I would look at a 3-way design. If these are woofers that came from a cabinet meant for bass guitar, then they are probably tuned to favor the lowest of the low frequencies. EV used to sell a 15" woofer & they had a model specific to the lowest low frequencies, and another that was designed to work better with the mids (while sacrificing the lows). I wonder if Peavey has the specs on their website. IMO, it's just tough to get an ideal sound with a 15" woofer and a HF compression driver - leaving out the midrange driver. You lose a lot of control of the midrange band of frequencies. Joe - if it were me, I'd put those woofers on eBay or Craigslist and forget about building a system around them. Tom "Music expresses that which cannot be put into words and that which cannot remain silent." - Victor Hugo Link to comment Share on other sites More sharing options...
Bill H. Posted December 9, 2011 Share Posted December 9, 2011 The point is though that Joe likes the sound of these speakers just as they are - in their original cabinet. The simplest thing to do (by far) is to just copy that cab - or split it in two if you want two separate cabs for each speaker. Peavey designed that cab for that particular Black Widow. As I said, Black Widow T/S parameters have changed a lot over the years - with the earlier ones having very tight Vas and very short Xmax to make them as efficient as possible with the low power amps of the time, and the later ones looser and longer to better handle higher power without damage. And each one requires a different box. Once you start adding horns and crossovers it gets complex and dicey. Link to comment Share on other sites More sharing options...
mate stubb Posted December 9, 2011 Share Posted December 9, 2011 Not to mention that if you add a piezo, you have recreated..... the KB-300. Moe --- Link to comment Share on other sites More sharing options...
JMcS Posted December 9, 2011 Share Posted December 9, 2011 So I'm wondering if it's possible to build two cabinets, one for each speaker and what geometry I should shoot for to get the best sound. Regards, Joe This might help: Loudspeaker Design Software. Link to comment Share on other sites More sharing options...
Joe P Posted December 9, 2011 Author Share Posted December 9, 2011 Thanks to all who have chimed in. I thinks it's safe to say that the problem of building a cabinet is much more complicated than I realized, even for this BSME who is no stranger to vibration analysis. Still, I have all the tools, a wood working brother who knows his stuff and an unrelated project coming up from which I should be able to cull the materials. Time permitting I'll give it a shot. There is something very rewarding about working on music related DIY projects. I restored a 5 piece set of Ludwig drums last winter and loved it. Regards, Joe Link to comment Share on other sites More sharing options...
ITGITC Posted December 9, 2011 Share Posted December 9, 2011 OHhhhhhhhh! Well, why dintcha say so, Joe? Go for it! Tommy "Music expresses that which cannot be put into words and that which cannot remain silent." - Victor Hugo Link to comment Share on other sites More sharing options...
Musicale Posted December 12, 2011 Share Posted December 12, 2011 If you go down the build them road, give Peavey a call, they probably have the required speaker parameters (free air resonance etc.) for cabinet design available, given the model/serial number of the driver... Regards, Musicale Link to comment Share on other sites More sharing options...
J. Dan Posted December 13, 2011 Share Posted December 13, 2011 Peavey Black Widow Specifications There are multiple models - see which ones you have. Assuming it's an 8 ohm, here are optimum vented enclosures for the 3 different models: http://www.that80sbandstl.com/images/mpforum/BWnums.jpg And corresponding low frequency response and max SPL: http://www.that80sbandstl.com/images/mpforum/BWgraphs.jpg Vb is the internal volume of the enclosure in cubic feet. Lv is the length of the ports in inches assuming two 3" inside diameter ports. The dotted line on max SPL is the thermal limit - based on power handling. So the mechanical limit (the graph) only applies when it's below the dotted line. Upper frequency response for all 3 is 2kHz, so you should be able to pair it with a horn for a decent 2-way design.... Something like this and this, the combination of which will cover 1kHz-20kHz with a max SPL around 129dB. Of course you'll need a crossover like this 1600Hz crossover would be about right, but you would need something like a 12dB L-Pad (comprised of 2 power resistors) to attenuate the horn due to it's higher efficiency. Of course if you have different black widows, this all goes out the window. You could also design/build your own crossover. The box designs can be modified to change low end cutoff as well as max SPL. For instance, raising the box frequency will increase MAX SPL at the point just before it drops off, but will raise the lowest frequency it can reproduce and create a bump in the response. Different port sizes and styles can be used, such as rectangular. Dan Acoustic/Electric stringed instruments ranging from 4 to 230 strings, hammered, picked, fingered, slapped, and plucked. Analog and Digital Electronic instruments, reeds, and throat/mouth. Link to comment Share on other sites More sharing options...
Joe P Posted December 13, 2011 Author Share Posted December 13, 2011 Wow, Dan, thanks. I don't have the electrics smarts to understand it all, but there are definitely pieces of information in there that I can make use of. Regards, Joe Link to comment Share on other sites More sharing options...
The Real MC Posted December 13, 2011 Share Posted December 13, 2011 I have a Peavey 2x15 bass cab. I got tired of reconing the Peavey speakers in it so I replaced them with heavy duty EVs. Can't stand Peavey speakers. Link to comment Share on other sites More sharing options...
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