I recently bought a pair of 15" Silver Iris coaxial drivers, but I'm less than satisfied. While they are very good sounding drivers, the mid-bass is just too muddy for me. I think this is due to the high Qts.
What alternatives are there that have a lower Qts? How about the BETA-12CX or BETA-10CX? I can't really find any reviews on how they sound.
Anything else in the $100 per driver range?
What alternatives are there that have a lower Qts? How about the BETA-12CX or BETA-10CX? I can't really find any reviews on how they sound.
Anything else in the $100 per driver range?
You might consider using the SI woofer as a bass augmenter with just about any fullranger on top to get the mids you are after. In one of my alignments, I use them as a 2-in-1 speaker. Fostex FE108's on top with the SI woofer for bass fill with just a 1st order filter. Then for loud listening, I flip 2 switches to cut the 108's and kick in the big coax with it's tweet using that stock XO.
I like the idea of a coaxial for the mid-bass/mids/highs and I already have 4 15's for bass duty. I'm just looking for another coaxial that has tighter mid-bass. It doesn't need to play very low. Flat down to 100hz is good enough for me.
How does the midrange of the BETA-12CX sound? I see the cone doesn't have any...ummmm, ring things (brain fart, can't think of what their called).
How does the midrange of the BETA-12CX sound? I see the cone doesn't have any...ummmm, ring things (brain fart, can't think of what their called).
I would cut the bass off that coax..@ 150hz or so..go active on those 4x15 " & then tweek it from there. If I had the Silver Iris I would use something line level or just complete active. Plates & something active for the fullranges & ability to bring in a tweeter of choice. JohninCR is lucky with his speaker mangement system. Extremely flexible. Vintage Alnico coax might be a good bet also as super high Qts is of not much consern if you go active bi-amp with plates or whatever. Alnico has a major tone differance to me for the good in the low mids & mids. yep I would go vintage.. or work that Iris over..
I have a full active setup, 6-channels. The SI's don't have the help of the 4 15's yet. I still need to finish(start) their ripole cabs.
Maybe I'll try high passing them even though I don't have a bass setup yet. I still think they will be missing that "snap" I'm looking for.
I would still like to know how the BETA-12CX would stack up against the SI.
Maybe I'll try high passing them even though I don't have a bass setup yet. I still think they will be missing that "snap" I'm looking for.
I would still like to know how the BETA-12CX would stack up against the SI.
What are your baffle dimensions and where have you located the SIs on them? Your experiences don't match mine with the SIs and I suspect you have a baffle problem not a driver Qts problem. Try a 18 x 38" baffle with the driver at 21" up from the bottom. This is where I found the best balance. As well OB speakers are sensitive to positioning - make sure they're more than 1 m out from the back wall.
For me the Hawthorne Silver Iris' produce a great open relaxed sound. They are even better with an additional 15" woofer to augment the bass. I couldn't afford Hawthorne's Augies but I very happy with the less expensive Eminence Alpha 15As.
My baffle is not optimal, its just temporary. 2'x4' mdf with 6" sides.
Before I made the baffles I had the SI's just propped up on a speaker stand. They didn't play as low, but the mid-bass still seemed a bit "loose".
Maybe I should hold my final judgment off until I build the ripoles. Hopefully they will provide the punch the SI's are lacking.
An externally hosted image should be here but it was not working when we last tested it.
Before I made the baffles I had the SI's just propped up on a speaker stand. They didn't play as low, but the mid-bass still seemed a bit "loose".
Maybe I should hold my final judgment off until I build the ripoles. Hopefully they will provide the punch the SI's are lacking.
I believe the muddy midbass is due to the high Mms, not Qts. Here an example of a 10" car audio free air woofer with lower Mms (probably not available in the US) that could be combined with a compression tweeter.
http://www.teleprodottistore.it/shop/ciare/cw250.pdf
http://www.teleprodottistore.it/shop/ciare/cw250.pdf
A resistor will Raise QTS, not lower it.
I found the formula in this thread: Driver Qt + Baffle size = Qts
JohnK writes in reply 17:
HTH
Doug
I found the formula in this thread: Driver Qt + Baffle size = Qts
JohnK writes in reply 17:
HTH
Doug
theAnonymous1 said:My baffle is not optimal, its just temporary. 2'x4' mdf with 6" sides.
Before I made the baffles I had the SI's just propped up on a speaker stand. They didn't play as low, but the mid-bass still seemed a bit "loose".
Maybe I should hold my final judgment off until I build the ripoles. Hopefully they will provide the punch the SI's are lacking.
The high Q of the SI is intended to extend the response of the driver when it is used on a small baffle. Your baffle is 24" wide with 6" wings, which is way too wide and will result in an exaggerated mid-bass response. Try removing the wings and see if you like the bass better.
If you're going to cross them over to ripole woofers, you might want to cut them down even narrower. Reduce the height, too. You need only a little more baffle above the driver than you have at the sides, more than that will just give more area for the baffle to re-radiate vibration.
Part of what you're hearing might be the baffle itself. MDF is not the best material for speakers, especially if it's a single, big, unbraced panel. Many SI users are using thick, well braced baffles to minimize vibration. A couple are working with constrained-layer damping. Others are decoupling the driver from the baffle altogether by building a free-standing magnet mounting bracket for the driver, and a separate free standing baffle, and using a thin strip of rubber or foak to fill the gap between the driver and baffle without allowing vibration to transfer between the two.
There are lots of photos in Hawthorne's forum, it's worth browsing around over there. Here are my current baffles. It's birch plywood, 17" wide with 4" wings at 45 degrees, 28" tall, with a center brace from base to top behind the driver. My next baffle will be both a bit smaller and much more heavily built.
Bill
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DougL said:
Doug,
That's series resistance. I'm talking about putting the resistance in parallel like Dick Olsner did with the Augies in his Feastrix based speakers because he found the Q of the Augies to be too high. though I haven't gotten around to trying the approach myself, I've also read that it can be a good tweeter tweak as well.
Looks like it's the BETA15CX I've been looking for all along. Exact same driver, lower Qts and Fs. I didn't realise the SI came from the same gene pool.
http://www.usspeaker.com/BETA15CX-1.htm
I'm not using the SI's XO and I plan to buy new compression drivers. What I'm left with is a BETA15CX with specs I don't want.
I'm going to try a 20R parralel resistor as a last resort.
http://www.usspeaker.com/BETA15CX-1.htm
I'm not using the SI's XO and I plan to buy new compression drivers. What I'm left with is a BETA15CX with specs I don't want.
I'm going to try a 20R parralel resistor as a last resort.
Personally, I think it's the big cone that can't deliver what you are after. It looks thick and pliable, which is in direct opposition to the small full rangers I have. There's nothing wrong with the laid back sound, and my SI's the easiest to listen to drivers I've had. However, like you I want it all, including the midrange presence and detail that my fullrangers deliver.
I'm pretty sure the SI's have a different cone than the Beta15. It's not just a beta15 with the next size smaller magnet.
I'm pretty sure the SI's have a different cone than the Beta15. It's not just a beta15 with the next size smaller magnet.
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