Turning off EXBAC on 340SE center.

[davef]

I'm vertically mounting my 340SE behind an acoustically transparent screen. I want it to have the same crossover as my 340SE mains.

Looking at the crossover, (yeah, I opened the speaker up, it's out of warranty anyway, and I'll never resell these) there is a toggle switch on it that is pointing up. On the my mains, it's pointing down. I assume pointing down disables EXBAC, so that's what I did on my center before I vertically mounted it.

Just posting this up here for future reference, verification or comdenation.

You can see the crossover in the attached picture, with the toggle switch pointing down towards the bottom of the speaker.

Brew, that is a good question, I look forward to some replies about the switch

Probably best to call Ascend on this.

I am sure they do not want people opening up their 340's on their own without a word of caution.

I completely understand.

It's just that if this was meant to be a user option, I am sure Dave would have posted about it, or even include it on the speaker's description page.

Giving people carte blanche to open up the speakers to change configurations, and not being able to track it, is not a good support practice.

Hi Guys,

A little behind as usual. Yes, with our 340 "SE" models, the toggle enables/ disables our extended baffle correction. It also changes the crossover point.

We don't consider it to be a user adjustable option simply because we only test the speaker in one configuration prior to shipping as it was never designed to be a user adjustable feature (nor should it be) That said, should someone need to switch from a 340 SE center to a 340 SE main, doing so is obviously not complicated.

[Jeff52]

Thank you Dave for explaining a very sincere request as to the switch, I had no intention of causing any kind of notion that it was OK to open up the 340's or any speaker from Ascends and altering the performance of that speaker. You answered my question thouroghly and simply, I did not know that the 340 mains and center are tested with and without the EXBAC and then shipped from your facility accordingly. I am not condoning any user modifications of your speakers, as a potential customer I just wanted to know my options and who better to ask than you, I again thank you for the clear and concise explanation of the question asked, Ascends is the speaker company that I have chosen to do business with, after an exhaustingly long speaker research investment I keep coming back to Ascends because of your customer support and caring what I have to say.
Best regards, Jeff

[S_rangeBrew]

Thanks for the confirmation, Dave.
If anyone is interested, I mounted my new "modified" 340SE Center vertically between the main 340SE's behind an acoustically transparent projector screen.

And it's glorious.

Everyone who can should do it.

[Gov]

I gotta be honest, I have read all the EXBAC threads (not many anyway) and I still don't feel like I totally understand it as it relates to current applications. Not many of us put a center channel on a modern display these days. TV's today are much smaller so it is not even possible. I think most of us (me included) put the center channel on top of an AV equipment shelf of some sort which is often in front of a TV that is mounted on a wall. The question is, does EXBAC benefit most of these applications?? Maybe Dave can chime in and put this issue to bed once and for all

[curtis]

Gov, with the way you have it mounted, on top of some fixture, and that fixture extends the front face of the speaker, then EXBAC will benefit.

Picture the front of the speaker as a plane, and when you place it on top of something, and that plane gets extended.

[Gov]

Gov, with the way you have it mounted, on top of some fixture, and that fixture extends the front face of the speaker, then EXBAC will benefit.

Picture the front of the speaker as a plane, and when you place it on top of something, and that plane gets extended.

Thanks Curtis, but what if I have the speaker placed right at the edge of the shelf so the front is flush with the end? Also, I have the 340 sitting on MoPads.

Thanks

[S_rangeBrew]

I'm wondering if modern EQ makes EXBAC obsolete in many cases. I'm thinking a system with over 10,000 EQ points per speaker (Audyssey XT32) would be able to correct anything the EXBAC was supposed to.

But then, I have no idea what I'm talking about.

[davef]

All good questions

I gotta be honest, I have read all the EXBAC threads (not many anyway) and I still don't feel like I totally understand it as it relates to current applications. Not many of us put a center channel on a modern display these days. TV's today are much smaller so it is not even possible. I think most of us (me included) put the center channel on top of an AV equipment shelf of some sort which is often in front of a TV that is mounted on a wall. The question is, does EXBAC benefit most of these applications?? Maybe Dave can chime in and put this issue to bed once and for all

Thanks Curtis, but what if I have the speaker placed right at the edge of the shelf so the front is flush with the end? Also, I have the 340 sitting on MoPads.

Thanks

I'm wondering if modern EQ makes EXBAC obsolete in many cases. I'm thinking a system with over 10,000 EQ points per speaker (Audyssey XT32) would be able to correct anything the EXBAC was supposed to.But then, I have no idea what I'm talking about.

From a technical standpoint, EXBAC gently modifies (3) aspects of the 340 SE main's response. First is that it changes baffle step compensation to assume that the speaker is going to be placed closer to areas of large reflections as compared to a main speaker. Second is that it gently reduces upper bass response within a range which is typical of bass reinforcement due to close proximity or enclosure placement (on a shelf, close to a wall, in an enclosure etc.). Reducing this type of bass reinforcement allows for improved intelligibility throughout the vocal range. And lastly, EXBAC adjusts the crossover point of the woofers to provide improved directivity when the speaker is used horizontally.

I would expect Audyssey and various other advanced room EQ processing to do a better job of compensating for speaker placement but this type of processing can not change the directivity of the speaker. Audyssey will probably render the bass reinforcement compensation and baffle compensation of the circuit moot (assuming it does its job properly) but that said, there is also no drawback to the EXBAC circuit. There is no reason not to engage the circuit unless you are using the 340 SE center in the same type of positioning as your 340 left/right mains.

Hope this makes sense

[S_rangeBrew]

That makes perfect sense Dave. I did not know that EXBAC did so many things. It sounds like turning it off probably was the right idea in my situation, since I'm mounting it vertically and using XT32.

Thank you for building such wonderful speakers!

[davef]

It sounds like turning it off probably was the right idea in my situation, since I'm mounting it vertically and using XT32.

Thank you for building such wonderful speakers!

I agree... and thank you for the nice comments