[versus rider]

as the title, I am looking for a suitable subwoofer that will go down to 20Hz and support my ob alpha's. It has to be for OB use as I have this crazy idea to mount one in the side wall of my azura bass horns, these work to 50Hz corner loaded. I may have to move them away from the corner with an OB subwoofer mounted this way. I was thinking to have just one in the centre between the open baffle/horns. It will have its own amp so no worries about spl levels.

[studiotech]

If you mount them in the side, open baffled won't you be facing the 90 degree side null?

Greg

[studiotech]

Also, I have no idea how loud you listen, but for single drivers per side, open baffle, they could have a hard time keeping up with a horn loaded system.  You are asking the most inefficient driver mounting style in its most power hungry region to hang with horns....not a good idea.  If you need some good bass below your horns, look into large sealed or ported cabinets placed back there in the corner.

[versus rider]

Also, I have no idea how loud you listen, but for single drivers per side, open baffle, they could have a hard time keeping up with a horn loaded system.  You are asking the most inefficient driver mounting style in its most power hungry region to hang with horns....not a good idea.  If you need some good bass below your horns, look into large sealed or ported cabinets placed back there in the corner.

Hi Greg, am just thinking out loud really, I'm not having any problem with my alpha's keeping up with the horns as they are tri-amped. 130w SS on the alphas, at present 300B for the 200Hz horns with BMS 4592 mid drivers and 2A3 on the 1000Hz horn with BMS 4524 drivers. So far on this hifi journey I haven't come across a box speaker that could hold a candle to open baffle bass, but then that depends on what ones taste is in that department. I am in the process of buying or making a pair of BD design compact bass cabs for another project so I'll see how that goes. I also am in the midst of building Azura bass horns to possibly replace the alpha's, but mostly its just curiosity. What about H framed alpha's and the like, how low to do they work well. 

[JohnR]

For those low frequencies I'd be inclined to try a pair on each side in some variant of a "W" type of frame.

The other trick is to move them closer.

[scorpion]

This is not an easy question, given all the years of Eminence Alpha 15 praise. In fact they sould be replaced altogether for best sound. Not the least in the higher range. So for a suggestion I would go for GR- Research Subs. Or I would advocate AE TD15Hs with ample EQ. I with the help of other's meanings I think that these are the best recommendataions. IF AE would be getting IB15s back there would be this choice only really.

It's a bit questioned all the time when I have favored the AE IB15 for superlative woofer output. But this is the case. All the way, from down to higher. And also for no coloration response.

/Erling

[JohnR]

It's a bit questioned all the time when I have favored the AE IB15 for superlative woofer output.

I guess I haven't been paying attention but why would that be (questioned I mean)?

[scorpion]

John, I guess I didn't formulate myself very well. It is not really aking to discussion here in AC more elsewhere.
The problem as I see it is that the Eminence Alpha15 has got an unfortunate satus as 'The OB Woofer' not really based on quality grounds.
But given relativly cheap digital technology, like mini-DSP, even a passive speaker could get EQed easy This certainly would result in a better performer in all respects if the EQed loudspeaker is a real good one..

/Erling

[JohnR]

Hi Erling, no worries, like so many things in this hobby decisions are made and reputation gained based on a very limited set of criteria. Cheap is good, of course, but with a little more budget and some investigation many other options open up... Based just on the modeling (I have neither driver myself) the IB15 looks about perfect to me, assuming the Lambda heritage translates to low distortion and aerodynamic noise and as long as there is enough power per driver. I wasn't aware that they were no longer available.

[studiotech]

John, I guess I didn't formulate myself very well. It is not really aking to discussion here in AC more elsewhere.
The problem as I see it is that the Eminence Alpha15 has got an unfortunate satus as 'The OB Woofer' not really based on quality grounds.
But given relativly cheap digital technology, like mini-DSP, even a passive speaker could get EQed easy This certainly would result in a better performer in all respects if the EQed loudspeaker is a real good one..

/Erling

I couldn't agree more Erling.  The Alpha15 is not really a good quality driver.  It just happens to have a really high Qts value, so it can make some bass in an open baffle without too much EQ.  End of story.  No other reason to use it other than it is relatively cheap compared to the better performing choices.  If you are low on money, buy it and have fun, but do not think that it is the "ultimate" choice.

One thing that frustrates me on a lot of the DIY forums is that price is always brought into the equation, sometimes to the ultimate exclusion of quality.  I see so many threads where the original poster asks about a driver or ponders a new design and the price hounds always jump in to show a lower priced product.  It might be that the original poster was not looking for the best value, but the best performance.  OK, rant over.

Greg

[versus rider]

the alpha is the only woofer I know and have/still use. I find it works better than any box speaker I have heard, with the exception of wilson watt puppies in a large room, not the owners room where he has problems with booming. It seems to me that OB bass does not affect the room as much as a box speaker. Question is which OB woofers of good quality regardles of cost would you suggest. With bracing on the magnets of my alphas as suggested by Rick I have clean bass to 350Hz. I would need a woofer that can do the same to mate with my 200Hz horn crossed at that frequency.

[THWO]

I use two Alpha 15A per side in my present open baffle model.

I finally came to the point to regard these woofers as the week point within this chain, as it seemed to lack precision, accuracy in comparison with the mid and treble.

Last week I recalled having heard an intense ringing either of the woofer or the midrange basket when I had to shut the music off with a sudden click after very loud hearing (telephone call coming in). After glueing 3mm felt mats with lots of hot glue into the inner sides of the wide metal sheeds of the Alpha´s and the midrange baskets and then additional 10mm condensed wool mat on top, I was surprised listening agani - a really serious improvement.

Although the magnets still are not braced, the entire reproductiongained in precision, accuracy, reality image. Of course, there still are much better drivers out there, but those simple and invisible adjustments made an audible big difference. The benefits of DIY, right?

Excuse my off topic - remarc as I did not contribute to the theme itself. I just wanted to comment positively on the recent replies...


Regards,
Till

[THWO]

Just if a matter of interest:



Till

[matevana]

Some high SQ woofers that come to mind, in addition to those already mentioned, are the Peerless XLS or XXLS series, The Peerless SLS series (if budget is a consideration), the Seas L26ROY and L26RO4Y, and the Daytin RSS line. I have used 3 of the 4 mentioned with good results in OB. I am currently playing with B&C pro sound drivers, particularly the neo magnet versions with high xMax, but they wont go quite as low as the others. They do offer tremendous efficiency, low moving mass and are built very well. They can also be uised much higher than the others mentioned with very good results.