Anyone use these OB?

[mayhem13]

Eminence Deltalite II 2512 Neo 12" Driver

Eminence Deltalight 12......fairly high Q and open frame. Pretty nice LF response vented but don't need below 100hz for this build, only up to 1.5khz. Any thoughts?

[Tytte71]

Here an example of the 15" version OBL11

[TerryO]

Here's the specs from your link:

Specifications: • Power handling: 250 watts RMS/500 watts max • VCdia: 2.5" • Le: 0.46 mH • Impedance: 8 ohms • Re: 5.04 ohms • Frequency range: 48-4,000 Hz • Magnet weight: 7 oz. • Fs: 37 Hz • Sensitivity: 99.9 dB 1W/1m • Vas: 5.2 cu. ft. • Qms: 3.13 • Qes: 0.44 • Qts: 0.39 • Xmax: 4.9 mm •

The Qts on this driver suggests that it is pretty low, not high.

Above 100 Hz it may not matter as much, but for bass performance you really would like to see a Qts above 1.00. The woofers on the later version of the Carver Amazing had a Qts of about 2.75 or so, with a Qms of 9 or 10, just to give you an idea of what's optimal for OB.

Best Regards,
TerryO

[mayhem13]

I guess i should have said......qts higher than most pro midwoofers.

Thanx for the response Terry and yes, 120hz on down is covered with sealed subs in stereo. What attracts me to these is as far as pro midwoofers go, the response up to 1.5 doesn't have that gradual rise requiring even further BSC which given an OB alignment would crush the efficiency of most midwoofers. And down low in a sealed box, these won't need a high pass filter at all,as Xmax isn't exceeded until ear bleeding levels so i nice blend to a sub without the interaction of LP/Hp filters.

What i'd like to know is how that rearward radiation sounds as these are a REALLY OPEN BACKED designed driver. Might even be TOO OPEN requiring some mechanical attenuation of the rearward radiation.

[CLS]

Hi/lo Q for OB is an old debate.

In almost all woofers we can get, the Qts is dominated by Qes, which cooperates tightly with the output impedance of the amp.

Yes, most amps available has a very low output impedance, so this factor is almost always ignored. But it can be changed (with so little effort and cost).

Low impedance drive + high Q woofer
High impedance drive + low Q woofer

Both can give the system Q you want. The choice is yours.

[TerryO]

Originally Posted by mayhem13

I guess i should have said......qts higher than most pro midwoofers.

Thanx for the response Terry and yes, 120hz on down is covered with sealed subs in stereo. What attracts me to these is as far as pro midwoofers go, the response up to 1.5 doesn't have that gradual rise requiring even further BSC which given an OB alignment would crush the efficiency of most midwoofers. And down low in a sealed box, these won't need a high pass filter at all,as Xmax isn't exceeded until ear bleeding levels so i nice blend to a sub without the interaction of LP/Hp filters.

What i'd like to know is how that rearward radiation sounds as these are a REALLY OPEN BACKED designed driver. Might even be TOO OPEN requiring some mechanical attenuation of the rearward radiation.

It makes a lot of sense to do it the way you're contemplating. Deep bass is pretty much non-directional and the harmonics produced by the OB will actually provide the directional cues for the upper bass. You may or may not want to try crossing it over just a little lower to see if it makes any difference, although the slope of the filter will play into that.

It's obvious you've put a lot of thought into it already, so it should work out well.


Best Regards,
Terry