A writeup on the GedLee Abbey 12 Loudspeaker Kit by our own Mike Galusha

Occam · « **on:** 4 Mar 2009, 03:40 pm »

The latest Enjoy the Music has an excellent writeup on the Abbey 12 speakers -
http://www.enjoythemusic.com/diy/0309/gedlee_abbey.htm

It actually makes me want to consider alternatives to my old warhorse Alons....

Mike - Many thanks,
Paul

mgalusha · « **Reply #1 on:** 4 Mar 2009, 05:58 pm »

Thanks for the mention Paul. I am still loving the speakers.

el-cee · « **Reply #2 on:** 7 Mar 2009, 12:50 pm »

Paul, thanks for the link.
Seems like Mike went above and beyond the build specs
to ensure a non-resonant cabinet. Wonder what Mike would
estimate the total assembly time, given the extra cuts for additional bracing?
I can appreciate the quest to minimize cabinet resonance, having just
completed a Rythmik/GR sub build using Danny's sealed sandbox design.
Also curious if any No-Rez or Black Hole was used for further resonance damping.
Thanks to Mike for a great article.

el-cee

Scott F. · « **Reply #3 on:** 7 Mar 2009, 01:32 pm »

Nice job Mike

Welcome aboard ETM

mgalusha · « **Reply #4 on:** 7 Mar 2009, 01:44 pm »

Thanks Scott. I up-sized your "stubby" stands from a few years back for the Abbeys, they work very well.

mgalusha · « **Reply #5 on:** 7 Mar 2009, 01:59 pm »

Quote from: el-cee on 7 Mar 2009, 12:50 pm

Seems like Mike went above and beyond the build specs
to ensure a non-resonant cabinet. Wonder what Mike would
estimate the total assembly time, given the extra cuts for additional bracing?
I can appreciate the quest to minimize cabinet resonance, having just
completed a Rythmik/GR sub build using Danny's sealed sandbox design.
Also curious if any No-Rez or Black Hole was used for further resonance damping.
Thanks to Mike for a great article.

el-cee

Adding the extra bracing and stiffeners probably added an extra 3 or 4 hours. I had a bunch of oak stair treads that were given to me when a remodel project failed. Not good enough for furniture use but perfect for this. I just set the table saw to rip them 3/4" wide and ripped enough to add 18 of them per speaker. It didn't take long to just run the planks through until I had a pile of 3/4" square oak. I used a stop on my miter fence to cut them to length, so that went really quickly as well. I attached them using Titebond II glue and a pneumatic brad nailer, so that also went quickly.

The crossovers took some time as I wanted to try and minimize the inductor interaction but the second one went much faster than the first.

I didn't use any other damping material as the foam Earl supplies is cut to fit the shape of the drivers and waveguide. Trying to cut out some Black Hole into pieces that would fit between all the stiffeners would be very time consuming, still I might do so one of these days. I have certainly thought about it but right now I'm enjoying them too much to mess with them. I still need to build my subs and the GR/Rythmik parts should be here next week.

Russell Dawkins · « **Reply #6 on:** 8 Mar 2009, 12:58 am »

I would imagine the combined volume of all the bracing would throw the tuning of a reflex box off by reducing the contained volume of air, but being sealed it just raised the f3 a notch.

James Romeyn · « **Reply #7 on:** 11 Mar 2009, 04:41 am »

Great review Mike! Very informative.

For those needing a sub system for the Abbey (or other main speakers): IMO Earl's mulitple sub advice is one of the most significant & cost-effective breakthroughs in audio. Three subs are the minimum for the mode-null effect (its mode-nulling effect can not be overstated or overemphasized). Powered subs (Polk IIRC) were mentioned in one of Earl's www.DIYaudio.com threads about six weeks ago; they had an original MSRP of $250 & were being blown out somewhere for $99. Earl posted that the subs mentioned would work fine as long as the ports were plugged & the LP xo poles staggered. (I'm pretty sure it would best to leave one port open, partly seal one port & seal the last port, thus staggering the respective Qs. Other siting & polarity points must be followed including one sub being sited above ear level but believe me it's worth the effort; the worse your modes the better the effect.)

turkey · « **Reply #8 on:** 12 Mar 2009, 04:03 pm »

Quote from: ro7939 on 11 Mar 2009, 04:41 am

Great review Mike! Very informative.

For those needing a sub system for the Abbey (or other main speakers): IMO Earl's mulitple sub advice is one of the most significant & cost-effective breakthroughs in audio. Three subs are the minimum for the mode-null effect (its mode-nulling effect can not be overstated or overemphasized). Powered subs (Polk IIRC) were mentioned in one of Earl's www.DIYaudio.com threads about six weeks ago; they had an original MSRP of $250 & were being blown out somewhere for $99. Earl posted that the subs mentioned would work fine as long as the ports were plugged & the LP xo poles staggered. (I'm pretty sure it would best to leave one port open, partly seal one port & seal the last port, thus staggering the respective Qs. Other siting & polarity points must be followed including one sub being sited above ear level but believe me it's worth the effort; the worse your modes the better the effect.)

Parts Express has some low-cost subs that looked reasonable too.

I'm listening to a pair of Nathans right now, and I think Earl's designs are killer! They are easily the best speakers I have ever heard.

James Romeyn · « **Reply #9 on:** 12 Mar 2009, 05:55 pm »

Looking forward to the pleasure of hearing Earl's speakers at the first opportunity. Duke LeJeune was his protege; his AudioKinesis line incoporate similar design philosophy (waveguide, etc). His $2500 SWARM 2.0 five-piece sub system is my favorite sub ever (the only known system to succesfully compensate for the room's boundary reinforcement below 100 Hz). Duke's Dream Maker (TAS Editor's Choice '08) & Jazz Module are among my favorite three to five main speakers.

Again, Earl's multi-sub philosophy provided the biggest performance upgrade ever for no out-of-pocket cost (it was my great forutne to have been building a sub system when first reading Earl's philosophy).

Mike, I have experienced the difference between two subs & three ala Geddes; the difference can not be overstated in a room like mine w/ bad modal problems & non-flex concrete floor & front wall. I imagine the less bad the modal problems the less great is the advantage.

Ric Schultz · « **Reply #10 on:** 12 Mar 2009, 07:37 pm »

Mike,
Some things you can try to extend the tweeter response:

1. Remove binding posts and hardwire....always more open and extended and dynamic sound.
2. Try your Behringer digital x-over......that way there are no caps, resistors and inductors in the signal path and you can play with equalization to bring out more top octave. You might be able to cross over even lower....say 700hz....with the steeper xover slopes.
3. Try a better compression driver. A friend A/Bed the B&C with the Beyma and preferred the Beyma for top end response and clarity.....the Beyma is the one that Duke uses....more money....of course.
4. Remove the foam and try some small pieces of felt on the inside of the waveguide........or buy some extra foam and make a hole in the middle so some sound comes directly at you without going through the foam but having the rest foamed will reduce bouncing waves in the guide. You can try just felting the outside lip of the waveguide as well.

Have fun,
Ric

sts9fan · « **Reply #11 on:** 12 Mar 2009, 07:45 pm »

Got my drivers in the mail yester day for my Nathan 10s!! These things are diesel!!
I cannot wait!

turkey · « **Reply #12 on:** 12 Mar 2009, 07:58 pm »

Quote from: Ric Schultz on 12 Mar 2009, 07:37 pm

Mike,
Some things you can try to extend the tweeter response:

1. Remove binding posts and hardwire....always more open and extended and dynamic sound.

Quote

2. Try your Behringer digital x-over......that way there are no caps, resistors and inductors in the signal path and you can play with equalization to bring out more top octave. You might be able to cross over even lower....say 700hz....with the steeper xover slopes.
3. Try a better compression driver. A friend A/Bed the B&C with the Beyma and preferred the Beyma for top end response and clarity.....the Beyma is the one that Duke uses....more money....of course.
4. Remove the foam and try some small pieces of felt on the inside of the waveguide........or buy some extra foam and make a hole in the middle so some sound comes directly at you without going through the foam but having the rest foamed will reduce bouncing waves in the guide. You can try just felting the outside lip of the waveguide as well.

So, in other words, just re-engineer the whole speaker.

That would kind of defeat the whole idea of buying Earl's speakers. It also assumes you know more than Earl does.

goskers · « **Reply #13 on:** 12 Mar 2009, 08:13 pm »

I totally agree turkey.

Earl is one of the best around that has considered everything from an audibility standpoint. He uses math and science to prove everything and his track record stands for itself. The fact that all of the subjective reviews are incredibly positive is kind of secondary to me.

Ric, if you ever get a chance to visit Geddes at his home and see his system then prepare to have your mind boggled. Listen first and let your ears tell you whats going on. Look second and see that it's powered by a 250$ receiver using cheapo connectors, wire and non-audiophile crossover components. Listen, look at the science and tell me that he's not on the right path to what really matters.

James Romeyn · « **Reply #14 on:** 12 Mar 2009, 08:22 pm »

Ditto turkey, goskers...

mgalusha · « **Reply #15 on:** 12 Mar 2009, 08:36 pm »

Quote from: ro7939 on 12 Mar 2009, 05:55 pm

Mike, I have experienced the difference between two subs & three ala Geddes; the difference can not be overstated in a room like mine w/ bad modal problems & non-flex concrete floor & front wall. I imagine the less bad the modal problems the less great is the advantage.

My sub drivers arrived on Monday and the amps yesterday, so I know what my next project is.

mgalusha · « **Reply #16 on:** 12 Mar 2009, 08:39 pm »

Quote from: Ric Schultz on 12 Mar 2009, 07:37 pm

Some things you can try to extend the tweeter response:

I'm entirely happy with the tweeter response. As for taking out the foam or cutting a hole in the middle. No. As the other folks has said, they are designed with this as part of a system. They do not sound good without the foam, unless your tastes run to bright and annoying.

turkey · « **Reply #17 on:** 12 Mar 2009, 08:53 pm »

Quote from: mgalusha on 12 Mar 2009, 08:36 pm

My sub drivers arrived on Monday and the amps yesterday, so I know what my next project is.

Keep us informed as to how it's going!

cujobob · « **Reply #18 on:** 12 Mar 2009, 08:56 pm »

Ric was just trying to be helpful, obviously, but I do tend to agree that leaving the speaker as-is would be your best route. Earl has discussed an A/B comparison done with the B&C compression driver compared to another high-end compression driver and most people couldn't tell the difference IIRC, the B&C was slightly preferred in that trial.

I believe Earl actually designs the crossover so that the high frequencies are tapered down a bit because a flat response with this type of speaker will appear 'bright' to most listeners.

JoshK · « **Reply #19 on:** 12 Mar 2009, 09:02 pm »

I've seen people infer the Beyma CP380 is superior to the B&C DE250 and I've seen people say the opposite.

Here is a post with links to data comparing the B&C and Beyma CDs. Judge for yourself.