I purchased a pair of CHR-70s for some near-field speakers for my PC. Now I'm considering box designs. I have a subwoofer and active crossover, so I can basically choose whatever crossover point I like.
My question is how much distortion are these drivers going to have below 80 Hz? It's my understanding that drivers this small have lots of 2nd order distortion when driven too low. Does anyone have this data for the CHR-70?
I see designs for these drivers that go down in the 40-50 Hz range, but if the distortion is too high then I'll just make a small sealed speaker and cross around 100 Hz. If they sound clean down low, then I'll make a larger ported box and cross lower.
My question is how much distortion are these drivers going to have below 80 Hz? It's my understanding that drivers this small have lots of 2nd order distortion when driven too low. Does anyone have this data for the CHR-70?
I see designs for these drivers that go down in the 40-50 Hz range, but if the distortion is too high then I'll just make a small sealed speaker and cross around 100 Hz. If they sound clean down low, then I'll make a larger ported box and cross lower.
I have no measures to quote, but I can relate that the CHR70 works like a charm in a sealed 5liter box.
specifically: http://homepage.mac.com/tlinespeakers/FAL/downloads/mMarS-1v0-map-231009.pdf
I was listening to a pair just last night on a 3 1/2W tube amp at a listening distance of about 8ft or so. They were running full range, with a small powered woofer ( CSS SDX7) XO around 100. The SPLs would probably equate to around the same you'd experience as a near field computer monitor, so Xmax limitations were not an issue, and I certainly detected no type of low frequency distortion.
Depending on your predilection, you might want to add some BSC, but Mark has done a pretty decent job of voicing these drivers to be very musical without, and with a powered woofer and in a very small room, I could certainly live with them as they are.
if you have the sub and the x-over, just put them in a sealed box and x-over 80 or 100Hz. I have them in 4 liters (with high pass cap, and with BSC), see post #101 in the http://www.diyaudio.com/forums/full...chr-70-application-thread-11.html#post1805742
I agree that if you have a sub you should just choose an 80-100hz crossover and not worry about it. However, I think it should be noted that I've heard 40hz cleanly come out of a design, with authority, that utilized the CHR-70.
I bet Lotus goes that low, the microTowers certainly get close, and there is at least one bigger ML-TL that surely should.
dave
dave
Yep...it does. Below that the roll off is quite steep but up until that point it's plain magnificent.
That's what I like to hear... still happy with them then old bean?
I designed and built the dual-chamber bass-reflex design and it does 45Hz from ~8L internal volume. And they sit nicely on the desktop, as I designed them for nearfield listening. I choose the DCR enclosure because it provides the xmax extension control of a smaller enclosure but the FR of a larger enclosure.
Thanks for the replies.
My current plan of record is a 6.6 liter box with a slot port tuned to 55 Hz. That's a compromise between space and low frequency extension.
I don't really "need" them to go below 100 Hz, per se, but if the drivers will do it then I figure why not? I can crossover lower for less localized bass and it gives me more flexibility if I want to use them in a different context in the future.
My current plan of record is a 6.6 liter box with a slot port tuned to 55 Hz. That's a compromise between space and low frequency extension.
I don't really "need" them to go below 100 Hz, per se, but if the drivers will do it then I figure why not? I can crossover lower for less localized bass and it gives me more flexibility if I want to use them in a different context in the future.
A little lumpy for my taste, even with the slot port to throttle things back abit. Going to make it harder to integrate with a sub.
dave
Attachments
The peak is only 2dB, is that really going to matter much? The driver response is more lumpy than that.
That is equivalent to a Q of well over 1.0 which is about as high as i like. Note the big rise in the blue curve -- group delay.
I'd be looking for something rolling off with a lower Q and at a place where i can use it in conjunction with the woofer XO. But that's me. Sealed 5-7 litre gives
dave
I'd be looking for something rolling off with a lower Q and at a place where i can use it in conjunction with the woofer XO. But that's me. Sealed 5-7 litre gives
dave
Hmmm, if I'm reading that right it looks like excursion becomes an issue pretty quickly as well.
I guess sealed is it for this driver in a box that small. Damn, I was hoping for a slightly more interesting build.
I guess sealed is it for this driver in a box that small. Damn, I was hoping for a slightly more interesting build.
Hi Preiter,
Much depends are where you want to cross, subject to your sub's performance. There's not much to be gained by running any smaller FR driver below 100Hz if the sub is in permanent use. In which case, a sealed box is most likely the viable and practical way to go.
There's plenty of audio guys out there using CHR-70 in smaller reflex boxes with no LF distortion issues under typical load conditions. Here's a pic of a new pair CHR-70 in Tony Wong's Oak wood 5.6 litre BR's. I'm trying these at home in Causeway Bay, Hong Kong. Very pleased with the results so far.
Mark.
Much depends are where you want to cross, subject to your sub's performance. There's not much to be gained by running any smaller FR driver below 100Hz if the sub is in permanent use. In which case, a sealed box is most likely the viable and practical way to go.
There's plenty of audio guys out there using CHR-70 in smaller reflex boxes with no LF distortion issues under typical load conditions. Here's a pic of a new pair CHR-70 in Tony Wong's Oak wood 5.6 litre BR's. I'm trying these at home in Causeway Bay, Hong Kong. Very pleased with the results so far.
Mark.
Attachments
- Status
- Not open for further replies.