Introduction and xover help

[gcarlberg]

After 5 or 6 years of arduous lurking ( although I see myself being more as a student) I've decided to introduce myself and showcase my latest project.

My name is George and I live and work in the Denver area. I has the opportunity to meet some of you last fall at the “Dîner de Soirée pour Honorer Greg Timbers”.

I found this site when I was driven to build some DIY speakers after finding several pieces of TOTL Pioneer separates form the early seventies that I had set aside during the kid years.

I started researching DIY loudspeakers and in the past 5 years have assembled about 12 pairs of Q&D and/or eWaves.

I finished my most recent project a couple of weeks ago when two boxes with freshly reconed E145's were returned from edgewound, mounted in 4CFT enclosures, driven with a 6290. These are mated with SAMH-1 waveguides and 2431drivers (sans 045’s). A pair of 2235's are crossed at 280, driven w a 6260 fill in the low end. I was currently using Zilch's Z19 crossover. However last weekend JuniorJBL spent some time auditioning and pointed out the crossover point seemed a little high. I pulled out the Z19’s and swapped in a M552. The missing octave was obvious however the M552 is noisy.

So I’m looking for a suggestion as what to use, either from an existing JBL product or maybe from someone’s similar build.

Thanks
George

[Robh3606]

Hello George

What do you have in mind?? What's doing the compensation on the 2431/Array Horn? Do you have any measurement software?? Passive may be tuff with 98db sensitive E-145's without doing a biamp with passive compensation up top.

Rob

[gcarlberg]

Thanks Rob,
When I was running the Z-19 crossover the all the drivers were dead quiet. However there was a serious hole around 1000k.

I swapped in the M552 and I have all kinds of noise (ground loop?) All connections are balanced. Household circuit is dedicated. I tried elimination ground with cheaters, changing polarity at the driver and in the crossover, etc in every possible combination.

I’ve using the 60 series compensation in the m552 for the 2341/Array.

I have the Behringer mic and HolmImpulse and TrueRTA for measuring

So I think I’d like to go back to a passive setup. What about using a AM6212/00 crossover clone? I could split the LF and HF and biamp.

George

[gcarlberg]

So after reading 4313b's "h9800 & 476mg" thread, I ordered a balanced MiniDSP to play with.

Thanks
george

[JuniorJBL]

Hey George

That new pre you have, is it balanced?

BTW I have all the components to build the compensation circuit if you would like. Rob's circuit is what I have been using.

You could also try the DBX 223 again if you would like.

Shane

[gcarlberg]

Hey Shane,

Yes, the pre is balanced, its an option on the pcb.

Thanks for the offer on the dbx, I think all just wait for the boat from China since there's no cd compensation on that unit.

g

[JuniorJBL]

Like Rob was saying above, It may be best to build Gregs comp circuit in the passive relm and see how that works with an electronic XO.

I think you can search "Gauntlet" if i'm not mistaken. Maybe someone else will correct me.

[Robh3606]

The Gauntlet was with the wrong horn 9800. Gregs Key filter is the holly grail and the starting point. I think I have something I did using Greg's filter as a starter, the AM crossover is too high and when you leave the inductor out you get a dip in the response. I have used the AM in my active set-up crossed at 1.5K where the notch doesn't matter. I will look around and post what I have.

Rob

[Robh3606]

Here is a work-up I did using the Array Horn and Gregs Filter as a base. It's been tweeked for my #5 2435 but that gives you an idea what you can do with it. As far as a passive with the E145 it probably has too much attenuation but in an active set-up it would not matter. I will post the original Key filter when I dig it up. The orignial poster would be 4313B.

Rob

[JuniorJBL]

Thank you Rob.

[gcarlberg]

This is enormously helpful, Thank You.

george

[4313B]

One thing I never did was run amplitude and impedance plots of the 2431/435AL versus 2435/435BE on the Array horn.

That filter above was derived when Greg unhooked the 045BE's in his Arrays and ran the 435BE's all the way out.

[Robh3606]

Hello George

You don't have any crossover software mentioned you might want to look at Jeff Bagby's software page. It's free and Excel based.

http://audio.claub.net/software/jbabgy/jbagby.html

Glad I could help.

One thing I never did was run amplitude and impedance plots of the 2431/435AL versus 2435/435BE on the Array horn.

Hello 4313B

I did that when I was building up my Array clones. I will post the amplitude when I get home

Rob