The Bordeaux - Crossover Help Needed - DIY Gurus please chime in

[Dave Bullet]

It looks like a winner to me

[ergo]

Very promising result indeed. The slight variations around 3.2k are probably from baffle edge and will be hard to do anything against without redesign of baffle but this might not very audible either.

[Mikerodrig27]

Wow, I am surprised that the manufacturer would change the tweeter like that. You think they would at least end the production of this model and give their revised tweeter a new model name or something.

Do you think it would be a good idea to use a tweeter from a different manufacturer and design a crossover around that?

[Jim Holtz]

Wow, I am surprised that the manufacturer would change the tweeter like that. You think they would at least end the production of this model and give their revised tweeter a new model name or something.

Do you think it would be a good idea to use a tweeter from a different manufacturer and design a crossover around that?

Actually, it appears that the production change was made prior to early 2017. Our development pair was the version previous to the change. The sin the manufacture committed is not publishing the new frequency response graphs for a reference for builders to go by. Our development pair matched the original published graphs closely. Curt is working on a temporary "fix" that will correct the crossover with a full fledged workup as soon as possible. He'll announce it as soon as its ready to go.

Also, anyone that buys parts from Meniscus will receive a tested pair to assure them they are getting the correct crossover to go with the AST2560 they purchased.

Why not dump it for a different company? To get a comparable AMT it would cost much, much more. The AST2560 is a killer sounding AMT and is built like a tank. It's worth the effort.

HTH

Jim

[Efalegalo]

Actually, it appears that the production change was made prior to early 2017. Our development pair was the version previous to the change. The sin the manufacture committed is not publishing the new frequency response graphs for a reference for builders to go by. Our development pair matched the original published graphs closely. Curt is working on a temporary "fix" that will correct the crossover with a full fledged workup as soon as possible. He'll announce it as soon as its ready to go.

Also, anyone that buys parts from Meniscus will receive a tested pair to assure them they are getting the correct crossover to go with the AST2560 they purchased.

Why not dump it for a different company? To get a comparable AMT it would cost much, much more. The AST2560 is a killer sounding AMT and is built like a tank. It's worth the effort.

HTH

Jim

Jim - I 100% agree with your comments. I think the AMT & Accuton and definitely a winning combo. I'm actually really happy with the way the above crossover sounds and can't wait for Curt to work his magic.

If I can complain about anything, it would be that the system a bit bass shy - but I think that is mainly because I'm coming from a floorstander that employs the Creative Sounds Solutions - SDX10 (with XBL^2 technology) - tuned to 23hz. I know it's not fair to compare a $220 high excursion woofer with a pair of $60 woofers. My brother is of the opinion that the Bordeaux are not bass shy, it's actually that the other floorstander is too bass heavy. In fact, after running the speakers for several days not, I think the bottom end of the Bordeaux have opened-up a little bit.

All in all, I really think it's worth waiting for Curt to re-do the crossover based on the same components.

[Efalegalo]

Bass!

.....If I can complain about anything, it would be that the system a bit bass shy.....

I take the statement above back.

So after experimenting with the speaker a little more, I decided I would take impedance measurements to check bass cabinet tuning.

DATs measured box tuning was 21.5hz. Utilizing WinISD, I modeled a pair of the Dayton RS225-8 (wired in parallel) in a 3.1cubic foot enclosure.

Per the directions of the Bordeaux kit, the inner tube of the 3" Precision Port tube is to be cut to 5", resulting in a total tube length of 11". The WinISD modeled exactly as DATs measured.

After confirming simulated response matches measured response, I decided to raise the tuning a bit. Given the Port flares, the shortest total length I could achieve was 6" (basically no inner tube, just the end flares). This results in a box tuning of 27.5hz. I wish I could go for a little higher turning, but then I would have to abandon one of the flares. Can't do that here because predicted port velocity is already kinda high (at max power that is - I'm sure at moderate volumes it should be an issue).

This significantly helps boost the bottom end. I think the bass is more in line with my preference now.

If I could do it all over again, I would go with a 4" Percision Port with a target box tuning of just under 30hz.

See graph below:

[Curt C]

Jim loves his bass, so all of the collaborated designs with Jim and myself have a slightly fuller, rich bass. Many builders have also found that the bass 'comes up' with the RS225's as the woofers break in. Give them time before you change too much...

- OTOH, feel free to experiment! That is the main advantage of DIY: The ability of modify a given design to suit your individual tastes and needs.

Remember: The room itself, the position of the speakers in the room, and the position of the listener in the room all contribute significantly to the apparent bass levels. Some experimentation with these parameters may reward the listener with a more optimal listening experience.

FWIW, I was a real bass head back in the early days. It took me quite some time to retrain my brain to hear nominally flat bass as optimal. While I still find excessive bass is more tolerable than a system lacking bass, I now perceive more bass as just more, not better.

C

[Efalegalo]

Final Crossover

After nearly 60+ hours of voicing, I finally settled on the following crossover. This was based on the best balance I could achieve for on and off axis response.

Minimum impedance (b/w the mid/tweeter) now is 5.6ohm.
The electrical phase is now within +/-30 degrees
Measured distortion is less than 0.1% at 95spl @ 1 meters
On-axis frequency response is +/-1db from 300hz to 20Khz.
There is excellent phase tracking between the mid/tweeter - resulting in a -30db reverse null measurement.

I'm super happy with the overall sound and even more happy that I didn't abandon the build.

[Curt C]

Very nice Efalegalo.

I hadn't had a chance to get back to finalize my crossover model, but it seems we were tending towards the same topologies. I'll double check to see if my model cooresponds with yours, but it should considering we are using the same measurement files. In the meantime...

I hereby proclaim we should call Efalegalo's crossover the one to use for new Bordeaux designs.

BTW, anyone who thinks 60+ hours of voicing is a long time... - It isn't.
Yes, its possible one can luck into the optimum crossover right out of the box, but that's only happened to me twice in all my designs.

Thank you Efalegalo for all your efforts to optimize the AST 2560 tweeter response issues in the Bordeaux design. I'm sure the forum appreciates it, and certainly Jim and I appreciate it as well.

Curt

[mlb3164]

You know it is very discouraging to find this thread about a month after ordering a Bordeaux kit from Meniscus. Now I know why he dropped them off his kit list immediately after I received mine. To top it off the two designers knowing there is a major issue with the tweeters allowed the kits to be sold knowing the speakers will NOT represent the original design. I guess I will just need to suck it up and build them and use Efalegalo crossover design. You get what you pay for in the DIY market right??

[Mikerodrig27]

Have you tried contacting Meniscus? From my experience, they have always been top notch with customer service. Now they measure every tweeter for this kit that is sold.

The Bordeaux speakers are worth the extra effort. Best of luck and I hope you are able to get your kit together properly.

[Mikerodrig27]

Also, this thread is very old so if you have just bought your kit within the last month, you should have the correct assortment of crossover parts.

[mlb3164]

I surely hope that Meniscus used this updated crossover schematic created by Efalegalo. It can get very expensive buying all new crossover parts over again.

[Mikerodrig27]

Yes, they are quite aware. I believe Jim had contacted them a while back. I know that it was mentioned on their site that they would measure every tweeter when ordered with that kit to ensure the correct crossover.

Send them an Email or call them. They are pretty reasonable.