I'm taking the liberty of starting this thread to help thunderpick see if he can use a speaker he got free for bass guitar.
He has been posting on an old thread originally about using sub-woofer speakers for this purpose, and I think this is causing confusion. The sub-woofer thread is http://www.diyaudio.com/forums/instruments-amps/83815-using-sub-bass-guitar.html
Briefly recapping thunderpick's first post about his speaker:
"I picked up a 15" Pro Studio speaker for free, it is a RM-065-241B 1999/12 SA 8 ohm Welton is the manufacturer, subsid of sony but Ill be darned if I can find didly.
I'm looking for schematics of the ecs 250 crossover on the peavey 118 sub hc cabinet. I love the thunder that cab gives with a peavey mark IV head. Building another cab with that 15 and 4 10's wanting full range. Haven't had any success finding the 1820 cab crossover, so please someone help!!"
I think I've found an identical unit on ebay that implies it's rated at 300W, but that's all. I've also posted these links for thunderpick to look at testing it, to determine its parameters, so he can nail up a right size box for it:
Measuring Loudspeaker Driver Parameters
One thing to watch is that Rod Elliott uses the word linear to mean two different things here... One is "the flat bit of the speaker impedance graph" the other is "speaker is being driven gently and distortion is low"
http://www.zeitnitz.de/Christian/scope_en
- soundcard scope with signal generator
NaTCH Engineering - SigJenny an Audio Signal Generator for Free
- just a signal generator
If this is a bit high-handed of me, then my apologies, it just seemed the best way to help thunderpick get his job done.
He has been posting on an old thread originally about using sub-woofer speakers for this purpose, and I think this is causing confusion. The sub-woofer thread is http://www.diyaudio.com/forums/instruments-amps/83815-using-sub-bass-guitar.html
Briefly recapping thunderpick's first post about his speaker:
"I picked up a 15" Pro Studio speaker for free, it is a RM-065-241B 1999/12 SA 8 ohm Welton is the manufacturer, subsid of sony but Ill be darned if I can find didly.
I'm looking for schematics of the ecs 250 crossover on the peavey 118 sub hc cabinet. I love the thunder that cab gives with a peavey mark IV head. Building another cab with that 15 and 4 10's wanting full range. Haven't had any success finding the 1820 cab crossover, so please someone help!!"
I think I've found an identical unit on ebay that implies it's rated at 300W, but that's all. I've also posted these links for thunderpick to look at testing it, to determine its parameters, so he can nail up a right size box for it:
Measuring Loudspeaker Driver Parameters
One thing to watch is that Rod Elliott uses the word linear to mean two different things here... One is "the flat bit of the speaker impedance graph" the other is "speaker is being driven gently and distortion is low"
http://www.zeitnitz.de/Christian/scope_en
- soundcard scope with signal generator
NaTCH Engineering - SigJenny an Audio Signal Generator for Free
- just a signal generator
If this is a bit high-handed of me, then my apologies, it just seemed the best way to help thunderpick get his job done.
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Personally, going through all that is a waste to just build 1 cab from a give away driver. Certianly not worth my time. Just buy or borrow a LC meter. If Le < 1 mH, the driver will probably have enough highs to make a decent sub cab. Getting a newbie to go to all the trouble of measuring driver parameters, which he'll likely not be able to finish because of the obstacles he comes across is a bad idea, IMHO.
Ok, well
Well, when I did this stuff previously, I actually found it quite interesting learning it.
I don't know how much thunderpick wants to get into it, but he self-evidently has the use of a computer, very probably a hifi amp. Apart from that the only other kit needed is some wire, a resistor, a multimeter and some simple free software.
Yes, maybe he'll find that the speaker he's got (anyone reading this got specs for it?) won't be much good for his purpose, then again, perhaps he just might. But he'll learn something, and know more about how this all works. Sounds ok to me, and I'm not twisting his arm or anything - if he thinks it looks like too much grief, then that's up to him.
Perhaps things have improved since I was doing this, some time ago now, but I found that speakers did vary somewhat from their spec sheets, to an extent that actually making the measurements was worth doing.
Well, when I did this stuff previously, I actually found it quite interesting learning it.
I don't know how much thunderpick wants to get into it, but he self-evidently has the use of a computer, very probably a hifi amp. Apart from that the only other kit needed is some wire, a resistor, a multimeter and some simple free software.
Yes, maybe he'll find that the speaker he's got (anyone reading this got specs for it?) won't be much good for his purpose, then again, perhaps he just might. But he'll learn something, and know more about how this all works. Sounds ok to me, and I'm not twisting his arm or anything - if he thinks it looks like too much grief, then that's up to him.
Perhaps things have improved since I was doing this, some time ago now, but I found that speakers did vary somewhat from their spec sheets, to an extent that actually making the measurements was worth doing.
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