Center channel for TI series

[duaneage]

The midrange to low crossover needs to be developed. A 104H driver can easily go to 750 hz with a 3rd order network. The crossover point needs to be carefully chosen to give good polar response with the three drivers. The best way to do this is with off axis testing of a mocked up baffle.

[rdgrimes]

Or have you just considered just buying an LC2 for the center?

I know from experience that the PC600 is an extremely close voice match. It has dispersion unrivaled by any other center. Currently available at HarmanAudio, but not cheap. What's your time and drivers worth? Those 108s are worth a small fortune re-coned.

Frankly, before spending time and money on a custom center for 250tis, I'd take a good while trying them with "phantom center" mode. they really are capable of running with no center.

[opimax]

I am attempting to make it look "factory" is why to build it. the 108 recones are currently paid for, allthough I could sell I would keep them for spares anyway. I guess "Just Because" is also a factor

Once the physical box is built Duane has "beaten" me to death to let him build my XO which I will happily do. I had bought some spare 120, 250tibq and maybe another (have to check inventory) XO thinking i would get help to modify 1 of them for this but I will sell the ones I don't need for potential spares (probably) to help pay for this.

I am currently using a beat looking but accoustically sound l250 converted to Ti for this but it blocks the view of the fireplace and breaks up a pair(although not being used anywhere), I was using 2 18Ti laying on thier side tweeter to tweeter , sounded OK at best,looked a little funny haveing 2 speakers where 1 should be too

please keep the comments coming

Mark

[JBL 4645]

I’d match up the frequency signature as close as can be within a few db± otherwise the tone from left and right matching speakers won’t match the centre and you’ll have holy mess on your hands.

Even if you have matching speakers the tone in someway shape or another due to location in the room will still play havoc with the tone.

It needs to be EQ either by lazy mans Adyssey because there are those who can’t be asked or manually EQ which can take days to perform.

You’ll need matching EQ for LCRS and a lot of tolerance as well as it can take days, to get done right. Well maybe not right just so that the frequency is within a few db of each other with no dramatic drops or peaks so that a single speaker will show more than the others. They should have equal tonal quality. its then down to how the mix is created.

I’d personally stick additional EQ in so that you can make custom adjustments without affecting the primary room EQ frequency response.

[rdgrimes]

I am attempting to make it look "factory" is why to build it. the 108 recones are currently paid for, allthough I could sell I would keep them for spares anyway. I guess "Just Because" is also a factor

Once the physical box is built Duane has "beaten" me to death to let him build my XO which I will happily do. I had bought some spare 120, 250tibq and maybe another (have to check inventory) XO thinking i would get help to modify 1 of them for this but I will sell the ones I don't need for potential spares (probably) to help pay for this.

I am currently using a beat looking but accoustically sound l250 converted to Ti for this but it blocks the view of the fireplace and breaks up a pair(although not being used anywhere), I was using 2 18Ti laying on thier side tweeter to tweeter , sounded OK at best,looked a little funny haveing 2 speakers where 1 should be too

please keep the comments coming

Mark

There's nothing wrong with "whim" as a reason to do anything.

So keep the drivers the same and keep the crossover points as close to the same as is possible. Personally I think the 108s are over-kill in a center, but they will lend some voice match in the low midrange. The critical matching will be in the 104, and it should be crossed over at points very near the 250ti points of 1400 and 5200. The 104 should have it's isolation box the same size as the 250's. I assume that having 2 108s in one box will alter the ideal volume of the box and possibly the XO as well. Since the 108s run in the limited range of 400-1400 in the 250, changing that range by removing the lower XO will significantly alter the required volume and XO tuning. The isolation box in the 250 is tuned for the lower limit of 400Hz. With that in mind, the 108s aren't really providing any significant voice matching, and a pair of 6" drivers might be easier to manage.

[opimax]

I believe the design for the 108 is an individual box for each woofer with its own port,think 3 seperate chambers, 1 for each woofer and center with the 104 and 44 vertical in the middle.

the 104 will have either a calculated area the size of the dog house from the 250 or an actual dog house from a 250.

Since it is a (most likely) 3 design the XO points will be the same as the 3 top drivers of a TIBQ XO currently in the 250. The XO will be external so the box will just have the drivers and speaker connections and can worked with at any time

original plans were to use 2 of the 6.5" woofer from the 18Ti but It was highly recommend not to and to use the 108s

I think the only issue left is the driver placement on the front. most of this will be driven by available space while trying to keep them as close to each other possible. I also believe while talking to Duane that he would have some input to that while testing for XO.

Mark