AE Speakers Dipole 15 or LO15 ? Need advice

[Face]

Where is the dipole peak for the AE woofers?

 

[superlian]

Where is the dipole peak for the AE woofers?

300 Hz in my baffle

 

[Face]

Unless you're unhappy with the sound(which you don't appear to be), I would lean towards keeping what you have now.

 

[superlian]

I was wondering if CD & horn from 800 Hz -> would give me more?
But the trade off is off coarse a dipole peak in the bass and less low end.

I could go 3 way with DSP (Groundsound) and use one XA30.5 on on the lower woofer from 300 Hz and down. The second XA30.5 on the upper woofer from 300 - 800 Hz.
Then i have another class A amplifier i could use with JBL D2 in Tractrix 400.

A lot of complex changes compared with todays setup who is working spendid.

But still, nothing is like midrange magic from a horn

 

[Gary P]

A little update.

... - 3000 Hz 18 dB to Radian 475 beryllium 1" in Autotech Tractrix 1000 horn...

Do you by any chance have frequency response measurements of the Radian 475BE? Preferably before EQ with low or no smoothing.

Thanks!

Gary

 

[superlian]

No, and i have searched unsuccesful.
In my Tractrix 1000 horn from Autotech with 3 order (electrical) high pass at 3000 Hz it has a very even response with a accoustical 4 order LR slope.

 

[johanwholst]

If you want to use the LO15's to 800 or higher in a wide baffle like yours, a 2.5 way configuration would be the way to go. Lowest woofer low passed well below dipole peak, and the upper woofer used all the way up.
D2 works marvellously in Constant directivity horns like Seos or JBL pt95. But it needs a lot of equalization in these horns/waveguides. Without DSP, you can more or less forget these types of horns. I dont know how D2 would behave in a tractrix horn, but in a seos 24, 800hz seems to be lowest usable crossover. For PT95, 1000-1500 is spot on with moderate correction for extension to 20k and beyond.

 

[Face]

The BMS coax can be used down to 450hz in a SEOS24, I'm surprised the D2's low end is that limited.

 

[johanwholst]

The purpose of D2 is HF duty. For LF extension (and the need of tweeters) I am sure there better drivers.

 

[superlian]

Hi Johan

Is even 800-1000 Hz to low for D2?
I thought it was much like other 1,5" drivers but with extended HF due to de dual diaphragms?
Is it any kind of crossover inside/outside D2 or is it only accoustical like a fullrange with wizzercone?

 

[johanwholst]

800-1000 would probably be no problem for D2 in the right horn/waveguide. M2 crosses over at 800 as far as i know. In pt95, 1500 seems to be the point that needed the least EQ, and it is exactly where I want to cross.
D2 is not a coaxial. The membranes play push push to reduce distortion and increase power handling
In my preliminary measurements, there are no apparent breakups in the range up to 20k. The rolloff is very smooth in the pt95, and easy to equalize

 

[superlian]

OK. So D2 does pretty much the same as f ex 2340H but with a little better HF, less beaming, higher breakup etc. A little step further in all diciplines due to the new double membrane invention?

I have tested Emilar 1,5" in Stereo-Lab 300 and there i didnt feel that a tweeter was that neccesary.

In a 400 horn the beaming problem will be even smaller with f ex 2340H.

 

[Face]

I was under the impression that beaming was due to the WG entrance size more than the CD used.

 

[superlian]

In any system like this I would be working with DSP for EQ, crossover, and time alignment. This is something some people shy away from and want to go with a passive system. There just aren't passive ways to go and correct for the rolloff and get the right phase throughout the crossover region. Something like the mindsp can work well as a simple option to experiment with. Other more high end options could work even better.

Here are 2 possible options I would look at. If it was simply a 2way or 2.5way system where the woofers had to play up to around 1KHz, I would choose the LO15. The cloth surround is free from a couple resonances that the foam surround has which would be an issue playing that high. I would use 2x LO15 per channel, bringing in the bottom woofer to start filling in below where the baffle step begins. This of course requires a 3rd amplifier channel but has some definite benefits compared to running both woofers this high. To cover down to 1KHz would require some kind of larger horn driver so the upper end wouldn't be open baffle.

For a 3way system I would use the 2x Dipole15 for more maximum output. I would cross over to the Dipole6 at the appropriate frequency based on the baffle step. This would typically be no higher than 300hz or so. At that point, both Dipole15's could be sent the same signal. I would then cross the Dipole6 to the RAAL dipole ribbon or AMT for the top end.

@ John

My LO15 have, as you know, foam surround. I understand that i get i little more x max than the standard LO15 but more sensitivity than Diopole15? And will it tolerate lowpass at ca 500 Hz without that foam surround resonances?

Secondly, my baffle is 75 cm wide plus the 30 cm deep back supports. Where can I expect the baffle step rolloff will start? I will use DSP but only one amplifier on the woofers with a zero ohm inductor on the lower woofer.

 

[mrgreenjeans]

Noticed that AE dipole published efficiency is 94db at 2.8V, not 88 db. Are you qualifying that spec by stating this it's the 2pi efficiency? I'm not that familiar with Dipoles and want to use this speaker in my next project. It would be good to know if their published specs are misleading. Thanks.

 

[Inductor]

I can give you a list of very accurate simulations specs for the references you need. Just name the drivers you want to compare.
http://www.aespeakers.com/products.php

 

[mrgreenjeans]

Nevermind. Stupid question. 94db-6db baffle loss equals 88db.