Supplementing center channel output

[chuckears]

The front soundstage of my modest HT is a pair of (crossover and tweeter diaphragm-upgraded) Fortes and (similarly upgraded) Academy. The Academy sat atop my big-box 55" Mitsubishi RPTV for several years (angled slightly downward for optimum effect), and served me very well.

When I recently switched to a 70" Sharp LED, the Academy was moved to the open shelf on the cabinet just beneath the new display, and I am a little underwhelmed by the output I am receiving from it. I have tweaked the angle of the center upward to assist, but either the change in position to being so low to the ground or the perceived larger display size (or both) are leaving me wanting a "bigger" sound... I am feeding the Academy with the 150-watt channel of a three-channel McCormack amp, and have tried more power from a pro amp, but did not like the sound quality compared to the McCormack.

Having limited funds available, changing the whole front soundstage is out of the question - as is changing out the stand I have in place for the display. Taking the RC64-II for inspiration, I have begun to wonder about building a couple of bookshelf-size speakers - the same height as the Academy - to place on either side of the center channel, each sporting a single woofer, with a horn tweeter in each placed on either end and in the same orientation as the tweeter in the Academy, and driving them with the other two channels of my McCormack amp (my HT Processor sports multiple outputs for the Center, so I would not have to worry about splitting the signal externally). The full orientation of the drivers would look like: [] O O [] O O [] - of course, not to scale.

The first concern I am facing is soundwave cancellation due to this untested orientation of drivers; I think it will be possible to minimize this issue by modifying the spacing and angling of the two flanking speakers, but would hate to find it untenable after the work involved in building the boxes.

The other concern I have is getting the crossover networks figured out; I built the upgraded crossover for my Academy - based on diagrams circulated in the forums, with assistance from Bob Crites - but I am assuming that the same circuit would not be utilized in a build that uses just one woofer instead of the two that are in the center.

I look for any thoughts or suggestions on whether or not I am looking at anything near feasible or reasonable...

[wuzzzer]

One thing to ask - have you checked to make sure you haven't wired the speaker out of phase with having to move it around?

I think almost everyone on here would not recommend what you're trying to do. Unless you add another Academy (and even that will cause cancellation issues like you mentioned) it will be almost impossible to integrate everything.

Post a pic so we can see what you're dealing with.

[Mongo171]

Your Academy should have no problem keeping up with your Fortes. My Academy has no problems keeping up with my Chorus II's. I think the placement of your Academy has negatively affected the sound of the speaker. Might be time to experiment with the placement of the Academy. My Academy sits in open air, not on a shelf in an entertainment center.

[chuckears]

Attached a photo of my setup; the Academy is pretty snug down there, and as I indicated, is tiltled slightly upward.

All connections are fine, and I have balanced the output with an SPL meter as always; the sweet spot still enjoys a nice, balanced sound, but for viewers/listeners off to the sides, dialogue is sometimes a little difficult to make out without turning up the volume to levels that can be a bit too much for anyone sitting in the middle.

Maybe it's the Mrs. and my own aging hearing, but I don't feel like the sound I'm getting fills the room like it did before.

Placing the center on the wall behind would look clumsy; setting it on the floor in front of the rack would be similarly ridiculous.

[iwander]

How about mounting the tv on the wall and putting the academy on the top of the cabinet. The academy would be closer in height to the Fortes.

[Daddy Dee]

Great looking sub. Is that a diy? How are you driving it?

[Daddy Dee]

Just to throw out a thought, if you end up building a center.... noticed that Parts-Express is selling the HF horn/driver from the KL-650-THX. A guy has also been selling these on Ebay.

http://www.parts-express.com/pe/showdetl.cfm?partnumber=279-106

Don't know anything about the suitability of the Klipsch soundbars, but one could be a very nice cosmetic match to your new TV. BTW, the room looks very good all the way around. like the music theme wall piece hanging over the tV.

[dtel]

What about just bumping the center volume up a little ?

Also it looks like the center cold be pointed up a little more, it's hard to see really, is it pointing at your ears where you sit.

[chuckears]

It's pointed pretty well to ear-level; I think imy disappointment might have more to do with the sound not filling the room as much due to the lower placement.

Thanks for the suggestions; the viewing distance lost by placing it on the wall would not be to my liking, but it would admittedly be better for sound output.

[chuckears]

Great looking sub. Is that a diy? How are you driving it?

Thanks; I built it with 13-ply Baltic Birch, the driver is a 15" Tempest-X, tuned to 16 Hz - definitely optimized for HT. It's being powered by one of the 750-watt channels of a QSC RMX2450 amp. The other channel is driving the other sub that didn't make it into the picture - an 18" Sonosub with a Dayton Titanic MkIII, also tuned to 16 Hz.

I don't have any complaints about my bass SPL []

...which might be contributing to my disappointment with the Academy output.

[Daddy Dee]

Great looking sub. Is that a diy? How are you driving it?

Thanks; I built it with 13-ply Baltic Birch, the driver is a 15" Tempest-X, tuned to 16 Hz - definitely optimized for HT. It's being powered by one of the 750-watt channels of a QSC RMX2450 amp. The other channel is driving the other sub that didn't make it into the picture - an 18" Sonosub with a Dayton Titanic MkIII, also tuned to 16 Hz.

I don't have any complaints about my bass SPL

...which might be contributing to my disappointment with the Academy output.

[Y]

[Daddy Dee]

Great looking sub. Is that a diy? How are you driving it?

Thanks; I built it with 13-ply Baltic Birch, the driver is a 15" Tempest-X, tuned to 16 Hz - definitely optimized for HT. It's being powered by one of the 750-watt channels of a QSC RMX2450 amp. The other channel is driving the other sub that didn't make it into the picture - an 18" Sonosub with a Dayton Titanic MkIII, also tuned to 16 Hz.

I don't have any complaints about my bass SPL

...which might be contributing to my disappointment with the Academy output.

[Y] [Y] [Y]

[chuckears]

Another angle, with the DIY Sonosub in the corner...

[dtel]

The piece above the Tv is cool looking, the CD holder in different directions is nice also, the room looks very nice. [Y]

[chuckears]

Thanks!

[wuzzzer]

Thanks for posting pics. Academy on top of TV stand. TV on top of Acacemy. Problem solved.

[Mongo171]

I like the TV on the wall, Academy and chatshkes on top of the stand. That Academy needs to breathe.

[garyrc]

The room looks too good, limiting your options as to
where to place the center speaker []. A center placed that low rolls
off the high frequencies (in most cases), due to treble beaming, even more so off to the side. It
doesn't look like it is sloped up very much ... can you slope it more?
Do your knees get in the way of the treble beam if you cross your legs?

Do you have
Audyssey MultEQxt or better (in your receiver)? If you used it, with
the eight microphone positions all at ear level, I'll bet it would give a
high frequency boost to the center, and make the dialog more
articulate.

I'm assuming you have no tone controls that affect the
center -- a big mistake on the part of the manufacturers, IMO. If your
receiver or pre/pro has any of those horrible, so called, Home
Theatre-EQ (Ht-EQ) options that actually turn down
the high frequencies sent to the center speaker because someone,
somewhere, thinks movie sound should be "mellow" and there should never
be even a trace of sibilance in the dialog, turn it off!

As to "bigness," 1) I'd think
the right and left speakers would contribute the most to that. It might
be a bad thing for the dialog to sound too "big," depending on your
definition of "big." 2) If the high treble is cut off due to the low
position of the center, the sound will be less spatial, therefore
"smaller."

The last time I
had a "small"/"big" problem (when I was 17), I wired a Centralab
"loudness" control into the TV, that gave me continuously variable
application of Fletcher-Munsen lower midrange and bass, as well as
switches that provided a choice of no boost, 8 dB high treble boost, or
12 dB high treble boost. It worked like a charm, and I had the biggest
sounding TV in the neighborhood (speaking through a JBL 030 speaker
system in a big Karlson front and rear horn loaded enclosure). But that was
then. I wouldn't recommend such radical surgery on our nice modern
components. They look too good.

[chuckears]

The room looks too good, limiting your options as to

where to place the center speaker . A center placed that low rolls

off the high frequencies (in most cases), due to treble beaming, even more so off to the side. It

doesn't look like it is sloped up very much ... can you slope it more?

Do your knees get in the way of the treble beam if you cross your legs?

Do you have

Audyssey MultEQxt or better (in your receiver)? If you used it, with

the eight microphone positions all at ear level, I'll bet it would give a

high frequency boost to the center, and make the dialog more

articulate.

I'm assuming you have no tone controls that affect the

center -- a big mistake on the part of the manufacturers, IMO. If your

receiver or pre/pro has any of those horrible, so called, Home

Theatre-EQ (Ht-EQ) options that actually turn down

the high frequencies sent to the center speaker because someone,

somewhere, thinks movie sound should be "mellow" and there should never

be even a trace of sibilance in the dialog, turn it off!

As to "bigness," 1) I'd think

the right and left speakers would contribute the most to that. It might

be a bad thing for the dialog to sound too "big," depending on your

definition of "big." 2) If the high treble is cut off due to the low

position of the center, the sound will be less spatial, therefore

"smaller."

The last time I

had a "small"/"big" problem (when I was 17), I wired a Centralab

"loudness" control into the TV, that gave me continuously variable

application of Fletcher-Munsen lower midrange and bass, as well as

switches that provided a choice of no boost, 8 dB high treble boost, or

12 dB high treble boost. It worked like a charm, and I had the biggest

sounding TV in the neighborhood (speaking through a JBL 030 speaker

system in a big Karlson front and rear horn loaded enclosure). But that was

then. I wouldn't recommend such radical surgery on our nice modern

components. They look too good.

The center is sloped upward as much as possible without risking interference with the top support bar of the display shelf (I purchased it online, using the dimensions listed for the product description, not visualizing that the heighth of that bottom shelf was from the base to the top shelf, with the width of the top support bar dropping down a few inches into the listed space); therefore, the woofers of my center are just barely clearing that top support bar; further sloping of the speaker would result in sound refection off of it.

NO tone controls are being used; I am a firm believer in sending as flat and full a response as possible to all speakers - I do have flexibility in tweaking the frequency response sent to each speaker group, and have adjusted the signal to the center a little by ear, to reduce a little of the "boxiness" by sending a little more of the high frequencies to the subs.

My HT processor came out just before ARC became available, so I do not have the fine-tuning available with the likes of it or MultEQxt.

Another solution I have considered, given my placement restrictions, is intercepting the center signal between processor and amp, and using a subwoofer crossover to pull the frequencies in the 40-80 Hz range to a dedicated sub for the center, placed either behind the display shelf or at one of the listener corners... my other two subs are tuned pretty low, and I am thinking I would get more clarity in the mid-sub bass by trying this option. I have read that odd mnumbers of subs after 2 are not good, but I have also read of success with mid-subs for the task I have just described. My biggest fear with this would be slight signal lag to the center from extra processing.

This has not been a huge annoyance, just part of my ears' seemingly endless quest to be 100% satisfied - probably not possible, given the plethora of mediocre source material...

[CECAA850]

Just for grins, you might make some additional feet (spacers) for your HT's legs. Take some 4x4's and slice off 4 chunks (or 6 depending on how many legs you have) and put them under your stand to raise it slightly and get your Academy off the floor. If you like what it does, you can make them look nice with a router for the corners and glossy black spray paint.