use of center channels as left, center, and right fronts

[joe_s]

I am considering the use of three "center" channels for use as left, center, and right to allow all three to be positioned below a projection screen. Any one doing this ?

Any favorite center channels to deliver as high volume / quality as possible ?

Thanks.

[joe_s]

It has occurred to me that a good bookshelf speaker angled back might work as well....i.e. pioneer S2EX.....not sure about availability of stand to support this profiel.

[Kal Rubinson]

Most "bookshelf" speakers are designed for vertical mounting. Rotating them horizontal will result in sub-optimal performance.

Kal

[joe_s]

Thanks Kal. I had assumed I could tilt them backwards. But will likely shift to all centers if i pursue this.

[Kal Rubinson]

Thanks Kal. I had assumed I could tilt them backwards. But will likely shift to all centers if i pursue this.

Depending on the centers (HTM1Ds are fine. :W ), you may be accepting speakers that are inherently poor in imaging and spatial integration. Many (most?) centers are.

Kal

[joe_s]

Thanks again Kal. The only three i have thought of so far are the HTM1D (which i have now), HTM2D, and the Pioneer S-7EX.

[Kal Rubinson]

In theory, those will do but I would want to try them out, all three across, and I wonder if there is any place in the world where that is possible.

Kal

[joe_s]

That is quite the challenge Kal. I doubt it. I had hoped I was not the first person to deal with this issue of speaker placement / screen width optimization, and could leverage other's experiences. Admittedly would prefer to listen myself, just not always practical.

[Kal Rubinson]

You might want to run this one by at avsforum where there's more traffic.

Kal

[kgveteran]

I have had very good luck and sang the praises of these guys.The dynamics are unbelievable.

My issue has always been the transition between the sub and the next speaker in the frequency response chain (the woofer of the main channel). With dual 8" drivers in each enclosure, this is a moot point.They can do 100hz all day at reference level ! I'm sure i could lower the XO point to 80hz with little difficulty.

Back to your OP you sure can run these like this.I've had them all horizontal and it's a smidge better, but I like em' the way they are now.

KG

[aud19]

Lot's of companies make speakers that they say can be used as centre and main speakers. Any of them could be an option.

If you can, I'd use 5 identical bookshelf speakers (oriented vertically) which is the optimal setup for surround IMO. It's just not always entirely practical.

[JRT]

I am considering the use of three "center" channels for use as left, center, and right to allow all three to be positioned below a projection screen. Any one doing this ?

Any favorite center channels to deliver as high volume / quality as possible ?

Thanks.

I would suggest using a 3way center that uses W-T/M-W configuration, the tweeter directly above the midrange, and woofers to each side of those.

The one below would be very good, because it would provide fairly even directivity characteristics in the horizontal plane, something that horizontal 2way MTMs do not provide.

[Kal Rubinson]

I would suggest using a 3way center that uses W-T/M-W configuration, the tweeter directly above the midrange, and woofers to each side of those.

Of course, that doesn't account for the lobing and interference between the mid and the woofers or, indeed, between the two woofers. Is each pair more or less than a 1/2 wavelength apart at crossover?

[littlesaint]

I would suggest using a 3way center that uses W-T/M-W configuration, the tweeter directly above the midrange, and woofers to each side of those.

The one below would be very good, because it would provide fairly even directivity characteristics in the horizontal plane, something that horizontal 2way MTMs do not provide.

What speaker is this?

[JonMarsh]

That's a design from Selah Audio in the RDU area, it's called the Sardonyx, intended as a center channel.

We've been working on something like that, but lower cost drivers in the Mission Possible area- using a very flat dome midrange, a new tweeter that's quite smooth to 30 kHz and 7" midwoofers with 3" voice coils similar to those in the Totem Acoustic Forest. Because it's using all Neodymium motor drivers, and because the crossover concept is based on Steen Duelund's 3 way all pass derived from one equation, and one damping coefficient, it's called the Modula CC NeoD.


It was originally intended as an HT center channel, but they sound so good standing up it's being adapted to that, too.


The second iteration of the crossover design has been done and tested, and is considered finalized; there are a couple of more versions coming, one using dual 4 ohm drivers wired in series for the midwoofers.

This is the developmental simulation of the individual driver responses and summed response (without ported enclosure to be used in final version)




This is the measured response with the final crossover of that developmental enclosure.












Most of the listening (all, actually) has been done in "music mode", not in CC mode, so far. A "build" thread should be going up before too long, as we complete documentation and go through the photographs to cull out what we'll use.

This version of the design is optimized for a small enclosure, and can be built with the pre-built 1 cu ft veneered cabinets from Parts Express, which have a removable front panel making assembly or testing much easier.

Image not available

[Hdale85]

One using dual 4" drivers????!!!!???? And the version you have now is a 6" mid isn't it?

[littlesaint]

I think someone needs some sleep :rofl:

He meant 4 ohm drivers wired in series.

I believe the current mid-woofers are RS180-8 or HiVi D6.8 wired in parallel. There is a 4 ohm version of the RS180 that is going to get a listen wired in series.

[Hdale85]

Oh...hmm well right now I think they just have a design for the HiVi D6.8.

[littlesaint]

Oh...hmm well right now I think they just have a design for the HiVi D6.8.

When the design is done, there is supposed to be builds for the HiVi, RS180-8 in parallel, RS180-4 in series, and non-BSC versions of the crossovers.

[JRT]

Of course, that doesn't account for the lobing and interference between the mid and the woofers or, indeed, between the two woofers. Is each pair more or less than a 1/2 wavelength apart at crossover?

I don't know the specifics of the design, but based on the assumptions below, the woofers are 71%-88% wavelength apart at the crossover to the dome midrange.

It uses Seas Excel W18 woofers. I'm not sure if they are W18E001 or W18EX001, but they both use the same frame, which has an OD of 176mm (6.93").

From the picture it looks like the space between the woofers is ~3/4 of the diameter of the woofer frame, ~12".

It uses a Morel MDM55 2" soft dome midrange, which I expect would be high passed in very high triple digit frequencies, the corner frequency probably somewhere in the range of 800-1000 Hz

For 800 Hz: (12" CTC)(800 Hz)/(13560 in/sec)= 0.71 wavelength

For 900 Hz it would be 0.80 wavelength.

For 1000 hz it would be 0.88 wavelength.



Here are some links:

link to description of Selah Audio's Sardonyx 3way center channel loudspeaker


on axis response measured above 200 hz shown below:




30deg off-axis response above 200 hz shown below:




Looking at this post, it might appear to people who don't know me that I might be trying to sell these. That is not the case. I have no affiliation with Selah Audio, and am not acting as a shill for them or anybody else.

[JRT]

What speaker is this?

Sellah Audio's Sardonyx

I should mention that I have no affiliation with Selah Audio, and am not acting as a shill for them or anybody else in this.

[Kal Rubinson]

I don't know the specifics of the design, but based on the assumptions below, the woofers are 71%-88% wavelength apart at the crossover to the dome midrange.

Could be OK. Getting the crossover down a bit would help that but put a bigger burden on the littel midrange driver.

Kal

[Spanky Ham]

Rick Craig is a member here. A PM might get the straight facts.