I have it matched with a tweeter that sounds great at low volume. Now we are in a large home and I enjoy my speakers particularly with amp32 playing guitar jazz (my favorite is Earl Klugh)
Here is the problem, at higher volume the cone seems to break up transiently, I am not sure how to put it... I don't think the amp is clipping. I notice either right or the left BOFU has the same problem.
Is this something that can be fixed with phase plug?, do I need to replace my beloved BOFU and move up from the budget king?
thanks,
gychang
Here is the problem, at higher volume the cone seems to break up transiently, I am not sure how to put it... I don't think the amp is clipping. I notice either right or the left BOFU has the same problem.
Is this something that can be fixed with phase plug?, do I need to replace my beloved BOFU and move up from the budget king?
thanks,
gychang
I have a hard time believing that the B20s are bottoming out here. I use mine on OB with copious amounts of EQ on the bottom end, and I get painful levels in room that create decent ambient levels throughout the rest of the house. In your Chang cabinets, you should have alot more cone control than on OB. You may want to look at the phase plug mod, if for no other reason than you'll be removing the pocket of air under the dust cap that will compress at higher level, resisting cone movement. Just a simple dustcapectomy would remove that problem, but they sound really weird without something filling that space over the pole piece, so why not phase plugs?
And, yeah, the Amp32 is probably underpowered for filling a large space. The B20s are not that efficient. PE states 90dB on their listing, but every set of DIYer measurements I've ever seen has been at least a bit lower. My rough, in my head, estimate is that the Amp32 pushing the B20s peaks around 96-98dB, so at only 4m away, that's down to 90-92dB and if you want your peaks much beyond that, you're going to distort and clip.
Have you tried your JVC with them in your new place. I'm sure they've got a good bit more juice than the Amp32. Maybe doesn't sound as good, but if its not exhibiting the same behavior, then you've got a definitive answer.
Kensai
And, yeah, the Amp32 is probably underpowered for filling a large space. The B20s are not that efficient. PE states 90dB on their listing, but every set of DIYer measurements I've ever seen has been at least a bit lower. My rough, in my head, estimate is that the Amp32 pushing the B20s peaks around 96-98dB, so at only 4m away, that's down to 90-92dB and if you want your peaks much beyond that, you're going to distort and clip.
Have you tried your JVC with them in your new place. I'm sure they've got a good bit more juice than the Amp32. Maybe doesn't sound as good, but if its not exhibiting the same behavior, then you've got a definitive answer.
Kensai
Greets!
I agree, at a rated 10% THD/14 W, I've 'cured' more speaker 'problems' with plenty of 'clean' power, so having a B20 collecting dust, I propped it up and connected it to a loaner 300 W/chnl Altec studio amp, rolled off the bass/treble controls and broke it in with some Eric Bromberg at ~85 dB avg/100+ dB transients/12 ft (diaphragm moving up to a finger gapped ~5/16 - 3/8" p-p) and to my ears didn't garble it any worse than at lower SPLs once doing the $0.98 tweak.
As always though YMMV, but if you like the speakers you owe it to yourself to try them with a low/no nfb amp with at least 25 squeaky clean watts and preferably at least the driver's 85 W in case you go crazy with some wide dynamic range symphony CDs.
Remember, the tweeter distorts/burns out first when a SS amp clips, so there's no such thing as too much power, just a point of diminishing returns.
GM
I agree, at a rated 10% THD/14 W, I've 'cured' more speaker 'problems' with plenty of 'clean' power, so having a B20 collecting dust, I propped it up and connected it to a loaner 300 W/chnl Altec studio amp, rolled off the bass/treble controls and broke it in with some Eric Bromberg at ~85 dB avg/100+ dB transients/12 ft (diaphragm moving up to a finger gapped ~5/16 - 3/8" p-p) and to my ears didn't garble it any worse than at lower SPLs once doing the $0.98 tweak.
As always though YMMV, but if you like the speakers you owe it to yourself to try them with a low/no nfb amp with at least 25 squeaky clean watts and preferably at least the driver's 85 W in case you go crazy with some wide dynamic range symphony CDs.
Remember, the tweeter distorts/burns out first when a SS amp clips, so there's no such thing as too much power, just a point of diminishing returns.GM
>>> I enjoy my speakers particularly with amp32 playing guitar jazz (my favorite is Earl Klugh...
I enjoy Earl Klugh also. Swap out amps to determine if it is the amp. If it is not the amp and you have grown tired of the B20 - I have not yet grown tired of my pair - at least you have an upgrade path to the Fostex 207e. Check all your other connections too just to be safe. Tell us more about the new room the speakers are in.
I think your amp may be too low powered for the speakers and the new room especially since the problem occurs when you turn the power up. Keep us posted.
Truly,
Godzilla
I enjoy Earl Klugh also. Swap out amps to determine if it is the amp. If it is not the amp and you have grown tired of the B20 - I have not yet grown tired of my pair - at least you have an upgrade path to the Fostex 207e. Check all your other connections too just to be safe. Tell us more about the new room the speakers are in.
I think your amp may be too low powered for the speakers and the new room especially since the problem occurs when you turn the power up. Keep us posted.
Truly,
Godzilla
it is amp32 clipping!!
as several have suggested, it is the amp clipping. Clean but small power t-amp chip is not enough for BOFU and my bigger home. Change to higher power amp (JVC) cured the problem.
I will put up some pics and more detail of my experience by this weekend.
gychang
BHTX said:
as several have suggested, it is the amp clipping. Clean but small power t-amp chip is not enough for BOFU and my bigger home. Change to higher power amp (JVC) cured the problem.
I will put up some pics and more detail of my experience by this weekend.
gychang
Yeah, especially given how beautiful your Changs are.
I don't think that the SI 2nd Gen T-Amp we're discussing in the other thread will be appropriate in this particular application. Its more powerful than my JVC, but not likely more powerful than yours (I don't actually think its more powerful than your Amp32, unless you're running it with a weak powersupply; if you are, upgrading the powersupply might be all you need).
Kensai
I don't think that the SI 2nd Gen T-Amp we're discussing in the other thread will be appropriate in this particular application. Its more powerful than my JVC, but not likely more powerful than yours (I don't actually think its more powerful than your Amp32, unless you're running it with a weak powersupply; if you are, upgrading the powersupply might be all you need).
Kensai
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.