Home High Efficiency Speaker Asylum

Need speakers that can rock with just one watt? You found da place.

Re: Eminence LAB 12 drivers

Hi Tom!

You wrote:

>> Part of the reason for my designing the LAB horn and specifying
>> the driver parameters was to give the Pro-sound DIY'rs a modern
>> bass horn, so many people interested in horns still follow the
>> old " folk lore ", like for example that a bass horn driver
>> should have low mass and small excursion capacity.

In all fairness, the reason that low mass is chosen is to extend the range of the subsystem and it is not merely a "rule of thumb." If this isn't important, then other design choices can be made.

>> At some point, the folks who did a shoot out in Michigan will
>> have the measurements and listening results posted on the basslist
>> so more actual data will be available soon.

Here are the measurements from the "shootout."

All products that were represented performed well. The LAB Sub appears to be satisfactory, as were all the others. But all products were also beginning to rolloff at 40Hz, with none of them better than 3dB down at this frequency. By 30Hz, all horns represented were at least 10dB down from their 80-100Hz midbass level. This is good response for a basshorn, but it is also important to point this out.

All-in-all, the LAB bass horn looks pretty cool and I can see how some people have gotten excited about it. And the $100 Eminence woofers are very reasonably priced, so cost of materials isn't high. But what about the cost of assembly and maintenance? How easy is it to build and service in the field?

>> I had just designed a variation on the LAB sub horn and got it in my
>> living room last weekend, a little smaller, only 42 by 42 by 18 inches
>> which also uses a "trick" in its operation. In room, it is unusually
>> smooth for a small horn + - 3 dB from 30 to 225 Hz and with 10 dB of
>> eq (no problem because of high sensitivity ~ 106 db 1w) the measured
>> response is - 3 dB at 22 HZ.

I see.

In room it is +/-3dB from 20Hz to 225Hz as long as there is 10dB EQ.

>> Using the TEF machine to measure phase and the Omnidrive (BS366) to
>> mate them, I got it aligned with the Unity horn system on top.

The impedance chart of the LAB horn shows several resonant peaks, which indicates that the device is reactive and that therefore phase is moving in these regions. This, combined with the long path length difference, makes alignment impossible without additional equipment. Even with additional equipment, such alignment would be a non-trivial task and would only be possible at one target location. We've discussed these issues many times before, but I felt compelled to respond to these comments here nonetheless.

This isn't terribly important to me, as you and I have discussed before. As long as the delay doesn't amount to a noticable echo and it doesn't cause response anomalies from 180o interference, I'm not concerned. So the fact that a horn's impedance has a reactive component at low frequencies isn't unattractive to me; I see it as a fact of life, like gravity and friction. But I feel that it is important to point out the fact that the Omnidrive product you've mentioned is a $3500.00 digital signal processor that you've undoubtedly setup to manipulate the signal quite a bit in hopes of making the system time aligned in the regions where the speaker subsystems are moving phase around the most.

Cool stuff! A little bit expensive, but definitely cool. Will you be taking all that equipment to Lima? I look forward to seeing you there!

Wayne


This post is made possible by the generous support of people like you and our sponsors:
  WEET Music Caps  


Follow Ups Full Thread
Follow Ups


You can not post to an archived thread.