Center Channel [Archive] - Lansing Heritage Forums

Val

05-31-2010, 04:48 PM

I've been reading up on this forum about center channels as I am not satisfied with my little B&W LM-1 I am using now in my 5.1 rig.

My right and left channels are LE15A/375/075 boxes. My sub is 2245H. My rear R/L are ceiling mounted Cambridge Soundworks 8" two way that will eventually be replaced so they are not a part of the equation.

I'm thinking of a two way box with two LE8ht's and one baby cheeks 2404. On one hand, I should probably use a 075 instead of the 2404 so the center will better match the R/L channels, but I like what I read about the character of the 2404 and the better dispersion.

The center channel box cannot be taller than 10" to fit between my sub and LCD. It can be as wide as 36" and up to 14" deep.

I don't have any of the drivers yet, so it is easy to change my plans at this point.

As always I appreciate any comments.

jblsound

06-01-2010, 06:53 AM

The hf and mid should match the L/R for proper sonic match across the front. The 2404 maybe better, but not if it doesn't match the mains.

robertbartsch

06-01-2010, 10:14 AM

....there are a couple of options worth considering. ....as said before, matching the center with the main speakers is ideal but, if not practicle, you could try for a reasonably good match. Getting the sensativitiies between the mains and center "close" is a good goal to consider.

How about a single 3-way 12" bookself speaker like the 4312, L100, etc.?

How about a 12 inch system with a horn loaded HF driver (2206, 2426)

On the later suggestion, I have one system similar to your mains running a center from a 12" 2206 and 2425 horn loaded in an old bookself system cab. I bought the empty cab on the Net for cheap, modified the baffle to accept a smallish horn and bought a commercially available crossover.

Val

06-02-2010, 10:28 PM

The hf and mid should match the L/R for proper sonic match across the front. The 2404 maybe better, but not if it doesn't match the mains.

I've been thinking about your comment. In theory I agree. But the street price of 375's and 075's are a bit much these days...especially the 375 and so it starts to break down for me in practice. Gonna have to think on this some more...

Val

06-03-2010, 12:07 AM

...if not practicle, you could try for a reasonably good match. Getting the sensativitiies between the mains and center "close" is a good goal to consider.

I like this...especially since I don't think I can afford "exactly matching".

How about a single 3-way 12" bookself speaker like the 4312, L100, etc.?

Got a pair of 4312's in the bedroom. Unfortunately the available vertical space is only 10".

How about a 12 inch system with a horn loaded HF driver (2206, 2426)

The vertical space limitations are why I'm thinking of compromising with an LE8T-H. I like the idea of the 2426 or similar.

Val

06-03-2010, 12:18 AM

. Getting the sensativitiies between the mains and center "close" is a good goal to consider.

The only sensitivity I have for the 375 is from the 1976 product brochure which lists it as 59db 1 Watt @ 15 ft. The 2426 has a sensitivity of 107 dB SPL, 1 W @ 1 m, JBL 2344A horn. I'll try to find the 375 sensitivity in the 1 W at 1 meter units so I can compare it.

robertbartsch

06-03-2010, 01:57 AM

you say your space limitation is 10"

Is this the space under your TV?

what about positioning your center speaker above the TV?

I did this and it works great.

....sensativities are impacted by the horn used in the measurement.....

jcrobso

06-03-2010, 01:38 PM

It's OK, for the most but suffers on music that is mixed LCR.
My mains are LE175 H/L and 077s, I'm going to try a 2123 in a sealed 1.5 cu ft box and a LE175 H/L for highs. The sensitivity of this would match my L & R speakers.
My mains have a high sensitivity(100db @ 1 meter) while the EC35 is 91db at 1 meter.
FYI, the 375 rating was using the old method at 15', most now use the 1 meter method. So I assume that the 375 would be about 107~109db by the current method.
You might want to consider using 2 JBL 2118 for this, the have a higher sensitivity than the LE8 and higher power rating.
http://www.jblpro.com/pub/obsolete/2118.pdf

jcrobso

06-03-2010, 01:39 PM

Allanvh5150

06-04-2010, 03:05 AM

I sit in a different camp. I dont really agree that the centre channel should match the L & R. The centre speaker has the bulk of the dialogue and as such a horn loaded top end is ideal. L & R have music, effects and off screen voice so I feel that a normal direct radiating setup is better. Try and squeeze a 2425/6 in there and dare I say it, hang it on the back of a 2370. As you only have a 10'' space to play with, a 12" isnt going to fit in there. Maybe go for a pair of 8" and a 2425/6.

Allan.

Val

06-04-2010, 07:59 PM

you say your space limitation is 10"

Is this the space under your TV?

Yeah, the sub is under the lcd tv and there is about 10" vertical space clear. The center can be pretty wide and deep but only 10" high. Hence my interest in the LE8th (plus others on this site have recommended it)
46116

what about positioning your center speaker above the TV?

I did this and it works great.

I have a very high WAF (note the 12 cu ft sub in the living room). The discussion was very short about putting the center over the LCD, so, the 10" vertical restriction stays...

Val

06-04-2010, 08:51 PM

It's OK, for the most but suffers on music that is mixed LCR.
My mains are LE175 H/L and 077s, I'm going to try a 2123 in a sealed 1.5 cu ft box and a LE175 H/L for highs.

Almost able to squeeze a 2123 into a 10" cabinet. It would be a little tight. Looking at the spec sheet it says the square dimension is 9 3/8". I would have to do some sculpting.

The sensitivity of this would match my L & R speakers.
My mains have a high sensitivity(100db @ 1 meter) while the EC35 is 91db at 1 meter.
FYI, the 375 rating was using the old method at 15', most now use the 1 meter method. So I assume that the 375 would be about 107~109db by the current method.
You might want to consider using 2 JBL 2118 for this, the have a higher sensitivity than the LE8 and higher power rating.
http://www.jblpro.com/pub/obsolete/2118.pdf

Thanks for the 375 sensitivity estimate. I had not considered the 2118. Thanks.

Val

06-04-2010, 09:37 PM

Maybe go for a pair of 8" and a 2425/6.

Allan.

Thanks

jcrobso

06-08-2010, 12:22 PM

Yeah, the sub is under the lcd tv and there is about 10" vertical space clear. The center can be pretty wide and deep but only 10" high. Hence my interest in the LE8th (plus others on this site have recommended it)
46116

I have a very high WAF (note the 12 cu ft sub in the living room). The discussion was very short about putting the center over the LCD, so, the 10" vertical restriction stays...
Looks like you lots of room up there!;)

Woody Banks

06-16-2010, 10:35 AM

I appreciate your space restrictions. Here is a MTM using dual 2118J's and a 2426H that would fit and a beauty currently on Audiogon that needs a home.:D

4313B

06-16-2010, 11:50 AM

http://www.tannoy.com/products/294/Definition_DC12i_Data_File_V1.06_Web.pdf

I appreciate your space restrictions. Here is a MTM using dual 2118J's and a 2426H that would fit and a beauty currently on Audiogon that needs a home.:DOh, that's cool too! :) And it probably beats the 6.5" Tannoy DC6i box that would actually fit in a 10" space.

Val

06-20-2010, 12:11 AM

I appreciate your space restrictions. Here is a MTM using dual 2118J's and a 2426H that would fit and a beauty currently on Audiogon that needs a home.:D

That looks just about right size wise. I think I missed it on Audiogon...not there now. What does MTM stand for?

jcrobso

06-22-2010, 09:23 AM

http://cgi.ebay.com/JBL-2118H-Midrange-Low-Frequency-Transducer-1-pair-/190407970740?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item2c55330fb4

Titanium Dome

06-23-2010, 07:14 AM

That looks just about right size wise. I think I missed it on Audiogon...not there now. What does MTM stand for?

I bet Woody knows where it is if you ask him. ;)

toddalin

06-23-2010, 09:51 AM

What does MTM stand for?

Midrange-Tweeter-Midrange, arranged symetrically, but usually in the vertical plane.

Val

06-24-2010, 11:04 PM

Midrange-Tweeter-Midrange

Thank you, that makes sense.

Val

06-24-2010, 11:10 PM

Here are some 2118H if you want to go that route!

Thanks!

Val

06-26-2010, 08:14 PM

I've just been re-reading this thread. I appreciate all of the suggestions.

Based on these suggestions I've put together a few scenarios. First off, I put together some of the specs for my existing R/L channels to help me think through matching sensitivity. I was not able to find the sensitivity for the LE15A or the exact freq range. I used the 2440 specs for the 375 and 2403 for the 075. I'm not sure if this is valid.

Val

06-26-2010, 08:24 PM

All of my scenarios use two 2118's in a symetrical layout.

This three way is as close as I want to get to my R/L. What I don't like about my existing R/L is that my 375's kick in at 500Hz but my LE15As don't give me much choice with that. Also, the 075's are a bit harsh and I've read here that crossing them over closer to 10kHz helps that. So, for these reasons, I don't want to exactly mimic my R/L.

For the center channel, the 2118's will allow the 2441 to be crossed over higher than my LE15A/375 crossover point. They will also fit in the available space.

I thought I'd go with a 2405 over an 075/2402 for the extended frequency response.

Val

06-26-2010, 08:29 PM

This scenario is still in the running. Mostly because I'm a sucker for the look of the baby cheeks and what I have read of it's character and dispersion. We tend to have a lot of people over at times and having wide dispersion is a plus. It's also probably the cheapest scenario.

Val

06-26-2010, 08:34 PM

Woody Banks

06-28-2010, 09:03 AM

This last scenario uses a more modern titanium horn. I have zero experience with them.

All of the crossover points are pure estimates based on on the response of the drivers. Love to hear comments on this.

I think my favorite scenario at the moment is the 3 way. Problem with that one is the expense of the drivers. It will take me a while to pull them together. But then again I'm not in a hurry and I love the process.

Except for the horn choice and the crossover point, your last two-way scenario uses the drivers I used for the center channel I posted earlier. It was the 4660 that was on AudioGon which sold for $700. You will probably see mine on there this week some time.
I used the 2118J's in parallel crossing over @ 1200Hz to the 2426 driver and OASR horn.
Check out the specs on the (Dr.Suess) OASR horn. They are fairly compact and perform quite well.

Woody

Val

06-30-2010, 10:01 PM

Except for the horn choice and the crossover point, your last two-way scenario uses the drivers I used for the center channel I posted earlier.

Yes, absolutely, I appreciate your earlier posts.

Check out the specs on the (Dr.Suess) OASR horn. They are fairly compact and perform quite well.

I did research the OASR horn on this site. Thanks for the tip.

4343

07-01-2010, 12:26 AM

This last scenario uses a more modern titanium horn. I have zero experience with them.

All of the crossover points are pure estimates based on on the response of the drivers. Love to hear comments on this.

I think my favorite scenario at the moment is the 3 way. Problem with that one is the expense of the drivers. It will take me a while to pull them together. But then again I'm not in a hurry and I love the process.

Not a big fan of the 2370A, personally. Big fan of the 2446.

LE-10's would fit in 10", same as 2123. I would want more low end than the 8" myself. Plus I have a pair I'm thinking of making a center out of...

Start saving now for the two 2405's (or 2404's) you will want if you put one in the center! (Have a pair of 2402's that have not seen use in years...)

Val

07-01-2010, 10:24 PM

http://cgi.ebay.com/JBL-2118H-Midrange-Low-Frequency-Transducer-1-pair-/190407970740?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item2c55330fb4

They went for $175...not to me:(

Val

07-04-2010, 02:59 PM

Val

07-16-2010, 12:12 AM

2404 arrived in good working order. I like the way it sounds. Now I need to scrape together the cash for a pair of 2118J's.

I just realized that the 2404 combined with two 2118's is used in the JBL 4612B in the Cabaret series. I'll take their lead and go with a 3k crossover frequency.

http://www.jblproservice.com/pdf/Cabaret%20Series/4612B.pdf

I started playing around with WinISD comparing a closed box vs. ported. Seems like a no brainer to me. Ported wins again. Blue line is ported, yellow is sealed.

Val

07-17-2010, 02:51 PM

I just bought a pair of 2118J's. They should be here soon.

Val

10-25-2010, 09:33 PM

Finally cleaned the garage and found the time to get back to this project.

I'm to the point of mounting the drivers on the baffle. The 2118's are mounting just fine but I'm not so sure about the 2404. I routed the hole per the cutout dimensions on the spec sheet. But, as you can see from the photo, the horn flange does not lie flat on the baffle. I'm tempted to bevel the inside edge of the baffle hole. I welcome any 2404 mounting tips.

481264812748128

pos

10-26-2010, 02:02 PM

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=46116
Hi Val,

I *really* like the design of your sub!
Would you have some plans or info to share on it?
I am planning on doing a pair of something similar for some 2245s :bouncy:

JBL 4645

10-26-2010, 02:27 PM

Val

These are the common compromises since home cinema started in the early 80’s one is placement of loudspeakers across the front.

The TV doesn’t matter if a CRT or flat screen it takes up space where a projection screen keeps sound image transparent as one.

All the clutter of four speakers LCR and subs are placed behind the screen, and out of sight!

The sound of pink noise when leaving the first loudspeaker should sound precisely the same when it arrives on centre and same with right and surrounds.

I see in your case its not going to happen :D with an another fine matching JBL placed in the centre then its sorted!;) From lows in effects or music that is placed in the centre not just the dialogue all the (DME) has to sound as one otherwise dialogue panning when it moves from centre to left/right is going to db miles off the mark.

That’s just heads-up on what to expect!

You’d be EQ for days!! To get the lows to sound the same from each speaker to highs. I’d listen to each LF LCR then mute LCR LF and listen to HF LCR the baby bum horn is going to be miles off.

Its got to have the same signature tone as the HF L/R otherwise some effects panning on highs will be too bright or dull when moving from left to centre or right to centre.

Otherwise nice little diy project I hope it hasn’t cost too much.

I hope you have DEQ2496 matching EQ for LCR because I don’t I have to make do with what I have on the DCX2496 and even that takes a few days with less EQ bands to deal with the issues. You’ll be EQ the LCR for weeks I promise you.:D

What happened to those other JBL speakers you had the control 10 was it? (can't tell you have so many JBL speakers):p Or was it the LSR series another one of those would be nice.

The Crown amp is that for the JBL left/right or for the sub in bridge mode?

I can’t see the sub clear enough. I see a long black box and what looks like cloth grill placed over a 15” or 18” sub or is that port hole?

pos

10-26-2010, 03:20 PM

Hi Val,

I *really* like the design of your sub!
Would you have some plans or info to share on it?
I am planning on doing a pair of something similar for some 2245s :bouncy:
found it:
http://www.audioheritage.org/vbulletin/showthread.php?25778-2245H-Sub-Woofer-Project

thank you

Val

10-27-2010, 10:56 PM

Hi Val,

I *really* like the design of your sub!
Would you have some plans or info to share on it?
I am planning on doing a pair of something similar for some 2245s :bouncy:

Thanks! It's basically a 12.8 cu ft box tuned to 30Hhz. Outside dim are 23" x 23" x 64".

Val

10-27-2010, 11:27 PM

Val
The sound of pink noise when leaving the first loudspeaker should sound precisely the same when it arrives on centre and same with right and surrounds.

The time delay issue you mention might be compensated for by my Integra DTR 30.1 receiver that has a setup mic and Audyssey 2EQ. It claims to correct time domain issues. I'll let you know after I get it setup.

Its got to have the same signature tone as the HF L/R otherwise some effects panning on highs will be too bright or dull when moving from left to centre or right to centre.

Otherwise nice little diy project I hope it hasn’t cost too much.

Yeah, I hear you and many of the other generous people on this this forum. My problem is that my R/L use very expensive drivers (075 and 375). That is why I didn't match the drivers to my R/L and went with the 2404. It is a compromise and, if I'm honest, I'm a bit bummed I didn't just save my pennies for a while a buy the 075 and 375. Or possibly a 2405 and 2421. Then build or buy a smith horn for the 2421:bouncy:. But, it is what it is right now. I'm happy to be building a speaker and look forward to hearing how it sounds.

I hope you have DEQ2496 matching EQ for LCR because I don’t I have to make do with what I have on the DCX2496 and even that takes a few days with less EQ bands to deal with the issues. You’ll be EQ the LCR for weeks I promise you.:D

Nope, no EQ yet. Again, the receiver has some basic EQ in the Audyssey RTA may help.

What happened to those other JBL speakers you had the control 10 was it? (can't tell you have so many JBL speakers):p Or was it the LSR series another one of those would be nice.

They are 4311's with a B&W sub in my bedroom and I'm listening to Snow Patrol on them as I write. They make great bedroom speakers.

The Crown amp is that for the JBL left/right or for the sub in bridge mode?

The Crown is for the sub which is a JBL 2245H. It is in bridge mode and has on-board DSP which I use to give a little 3db bump and roll off LF at 20 HZ at 48 db/octave to protect the driver from DC.

Val

11-25-2010, 09:54 PM

Finally making some progress. Mounted the 3k 2 way crossover. I've since added quite a bit of fiberglass damping material.

Val

11-25-2010, 09:56 PM

Primer...

Val

11-25-2010, 10:06 PM

jblsound

11-26-2010, 05:33 AM

Looking good! But I wonder if you should have used flared ports, which cut down on port noise? I used flared when I built a pair of ported subs.

Val

11-26-2010, 02:48 PM

Looking good! But I wonder if you should have used flared ports, which cut down on port noise? I used flared when I built a pair of ported subs.

So far I've not been able to detect any port noise.

jblsound

11-26-2010, 03:29 PM

So far I've not been able to detect any port noise.

Well, that's good then.

jbl_daddy

11-27-2010, 07:31 AM

jblsound

11-27-2010, 08:34 AM

Does your crossover cross one of the drivers at one frequency and let the other travel all the way down? I am building a similar center for my theater as well. Current I am using a pair of l65, but that will soon change.

Doing that for a full range mains, like the Everest II is good. But my way of thinking, not for a center channel, which is mostly dialogue. Both mid-range/bass drivers should operate over the same frequencies.

Val

11-27-2010, 07:40 PM

Doing that for a full range mains, like the Everest II is good. But my way of thinking, not for a center channel, which is mostly dialogue. Both mid-range/bass drivers should operate over the same frequencies.

Are we talking within the Center Channel? The 2118J's are wired in parallel and connected to the LF portion of the 3k crossover (12db/octave Linkowitz/Reily) and the 2404 to the HF output. Is the suggestion to run the 2118's full range?

jblsound

11-28-2010, 04:32 AM

Are we talking within the Center Channel? The 2118J's are wired in parallel and connected to the LF portion of the 3k crossover (12db/octave Linkowitz/Reily) and the 2404 to the HF output. Is the suggestion to run the 2118's full range?

Yes, within the center. My thoughts are as you already have it, in parallel down to 80 htz, as the FR for the 2118 is to 70. I would not play them below 70 in a HT setup.
For music only, I have run my L212s full range at times w/o a sub. The 112A in that system is like the 2118 w/FR to 70 but 6db/octave slope.

jbl_daddy

11-28-2010, 12:07 PM

I have had my crossover built and the question was asked if I wanted the 2118's in mine stepped in frequency like a 4612 , we did not instead designed them to both run together. The other two elements in mine are a 2420 and a 2405. Christmas project...

JBL 4645

12-02-2010, 11:01 AM

I tuned it to 100 Hz. It sounds great. I love how vocals come across on the 2404 and also how it has great dispersion. I watched Stop Making Sense by the Talking Heads...very nice.

It certainly does sound different from my R/L channels. I'm finding it a good exercise for my ear to listen to the differences. Maybe on day I will build another center that matches!
Val
I told you so.:D Well at least it works that’s the primary goal here isn’t it?;)

It’s going to miss or maybe miss so lows down at 20Hz going upwards body punches or deep Schwarzenegger lies “he’s using the trees”. lol

Why not matching pair and flip them all upright I know the flat screen gets in the way of the sound action. Make them flat still doesn’t improve the sound to picture. Why not compact smaller tighter meaner JBL with 12” and small HF horn that rests on top of the enclosure, fixed horn tweeters suck because you can’t tilt them you have to tilt the whole speaker!

Still you are show-off with that new diy JBL:p :applaud:
:happyh:

JBL 4645

12-02-2010, 11:15 AM

Doing that for a full range mains, like the Everest II is good. But my way of thinking, not for a center channel, which is mostly dialogue. Both mid-range/bass drivers should operate over the same frequencies.

Rubbish! Who told you it was for just dialogue? If you’re system has the means of switching monitoring any of the LCRS/LFE.1 at will! Then monitor closely the centre in discrete Dolby digital its miles different over Dolby 4.24. matrix, where the music or some effects will crosstalk or fold onto the centre discrete original mix.

Switch to Dolby digital discrete and listen to only the centre you’d be hearing a whole lot more besides dialogue. Effects and music will be like wow to you’re ears.

Listen to, Indiana Jones and the Last Crusade (1989) that has dialogue panning over the LCR to where the onscreen images are placed and it is such and incredible Dolby film mix still to this day. Its better still with projection screen covering the matching fronts as the sound images become one.

:tree:

roscoe1224

12-02-2010, 03:52 PM

i know its off topic but i wish i had as much real estate for a sub and equipment as the OP. i'm jealous.

JBL 4645

12-02-2010, 04:17 PM

i know its off topic but i wish i had as much real estate for a sub and equipment as the OP. i'm jealous.

I second that I’m deeply jealous my living room is tetchy. But I make do with what I have make do with what I have and make it work within all four-walls, oh not forgetting the floor and ceiling. :D You hear that, Val we’re deeply jealous :p we want rooms the size of yours. How big is your room Val it looks to be 15 wide by 20 feet long with low ceiling around 8 or 9 feet?

I think the smaller the room the better, less power to drive the speakers. Bigger rooms more power maybe? Still every room has its null and frequency response issues to tackle. I don’t know what, is worst larger rooms or smaller rooms.:dont-know:

:tree: