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miatagreg
02-01-2005, 12:07 PM
I have a pair of Olympus 8SR's that I will be using for both music and as the front L/R speakers for my home theater.Any Ideas on what to use for a center channel?

Zilch
02-01-2005, 12:23 PM
Paragon would be good. You could run it mono. :)

GordonW
02-01-2005, 12:29 PM
Urei 813? A coax monitor would seem to be a good plan...

Regards,
Gordon.

miatagreg
02-01-2005, 02:02 PM
I have a pair of Olympus 8SR's that I will be using for both music and as the front L/R speakers for my home theater.Any Ideas on what to use for a center channel?

Yes a paragon would be nice Zilch, but it would be totally impractical and way out of my budget.Do you have any idea of how much a Paragon sells for these days?

thanks anyway

Zilch
02-01-2005, 02:45 PM
It's gonna be hard to match the sonic character of S8 without building something. LE15, 375, 075. I'm SURE we can come up with something MTM for a center here.... :p

speakerdave
02-01-2005, 07:17 PM
Yes a paragon would be nice Zilch, but it would be totally impractical and way out of my budget.Do you have any idea of how much a Paragon sells for these days?

OK, so what are the practical parameters? How about an 075 stacked over a 375/2440 on a 2311 with 2308, flanked by a pair of 2202's?

David

miatagreg
02-01-2005, 10:21 PM
the primary consideration is size. So......


How about an mtm using 2 LE8T's and an 075(or an LE20)?

OR

an LE 12 with an O75 or LE20 stacked (or possibly a 175)

OR

an LE12C??

I want to timbre match as closely as possible without jeopardizing the favorable WAF(Wife Acceptance Factor) of those two large C-50's that I currently enjoy and without breaking the bank . Anything that I do will be a big improvement over the current center channel.

speakerdave
02-01-2005, 10:33 PM
All the units you mention are Alnico. Is that a personal preference? Or are you using a CRT TV?

David

miatagreg
02-01-2005, 10:52 PM
I do have a CRT TV.I want to timbre match with the 8SR's fo I figure that these would be a good place to start

Steve Gonzales
02-01-2005, 10:59 PM
I would have traditional horizontal enclosure loaded with 2 K110's, 1 LE85 or some other medium sized comp driver mated to a 2370 and a 077 or a 2405. crossed over at 800-1k and 7k. The 110's on the outside, the LE85 inthe middle with the 077 on top of it. Or if you used the H91/L91 combo and crossed them over at 1200hz you could have something that matched

Zilch
02-01-2005, 11:36 PM
See center channel here for conceptual format:

http://audioheritage.org/vbulletin/showthread.php?t=3774

Build with alnico drivers, mount above CRT angled down.

TimG has some 2380A horns for sale....

speakerdave
02-02-2005, 12:41 AM
LE8T's are all pretty old and are no longer reconable. Most of them have probably been or need to be refoamed and therefore will very likely not perform according to original specification. The LE10A frame is fairly common and would be a better choice I think; refoaming these is also a problem, but I think the LE10H cone kit can be made to work in the Alnico frame (I must defer to others for affirmation of this). Maybe Earl K will check in with comments about a pair of these with the aforementioned LE85 on a 2307 with a super tweeter added.

This would be fairly inexpensive but would not truly be a dynamic match with your big speakers. I think the center channel in an HT setup carries a goodly share of the load; it should truly be able to run with your main speakers.

For that my original suggestion is still viable, I think, although the Alnico 2202 is a rare bird. That setup would come in under a grand. I believe there are other alnico frames that could take the 2202 kit (K120, 2130, D131 I THINK). That or something very much like it would be a good match and would be most satisfying in the long run.

If you really want to go low dollar find a singleton L100. The early ones are all Alnico or have an Alnico woofer and midrange with a ferrite LE25 tweeter. You might be able to substitute an LE20 in its place. It would surely beat out what you are contemplating with LE8's and LE20's. If you didn't like it you could pass it on and it wouldn't have cost you anything, or very little, to try it. A single L77 would be another possibility.

David

Mr. Widget
02-02-2005, 01:21 AM
I would say voicing is key. The mini-woofer/tweeter/mini-woofer that most centers use is to control the dispersion... If you use a 10"-12" woofer that can go to 80Hz, a 375(2240) and HL93 (2308/2311) and either 075 (2402) or 077 (2405) you won't have to worry about dispersion, and if they are all vintage alnico, no worries about stray magnetic fields.

You should be able to put the system together in a 2 cu ft box, say an old L-100 if you aren't a constructor or the box of your choice if you are so inclined. If you choose the right woofer it should sound quite a bit like your S8Rs. I think I would go with the LE10. You will need to really pad down the two horns, but it should really sing.

Alternatively a single 4310 or early L-100 as Speakerdave suggests would be an easy fit.

Widget

John
02-02-2005, 03:11 AM
Correct me if I am wrong ,but the centre channel is mostly for the dialog of a movie track? If so would you not want something that is designed for speech reproduction.http://audioheritage.csdco.com/vbulletin/images/smilies/scratchchin.gif

Mr. Widget
02-02-2005, 10:42 AM
Yes there is a lot of dialog coming from the center channel, but as an actor moves across the screen sometimes the voice is panned from one speaker to another. For best effect you want all three primary speakers to be identical, or at least very similar. In real theaters they typically have five identical speakers behind the screen... their screens are bigger. :D

On top of that, the 375 and HL93 are superb at dialog.:)


Widget

John Y.
02-07-2005, 08:58 AM
I would say voicing is key. The mini-woofer/tweeter/mini-woofer that most centers use is to control the dispersion... If you use a 10"-12" woofer that can go to 80Hz, a 375(2240) and HL93 (2308/2311) and either 075 (2402) or 077 (2405) you won't have to worry about dispersion....
Widget

Mr. Widget,

Exactly how does the M-T-M array control the dispersion? Wouldn't the cancellations of having two woofers (Mid/woofers) cause irregular response off axis. My thinking is that at a low crossover point to the center, this would be minimized, however, at what point? 500 Hz? 800 Hz?

Thanks, John

Mr. Widget
02-07-2005, 11:29 AM
Off axis cancellations is exactly what they do cause... that is the point. They are typically taking a wide dispersion dome and trying to limit their dispersion. Since we typically work with horns, the horn acting as a wave guide controls that for us.

As to what frequency to lessen the effect? Not sure. Certainly the lower the better. For JBL's Hercules system they use a pair of 10s up to 800Hz mating with the H9800 horn and they have deemed that acceptable.

Widget

GordonW
02-07-2005, 12:24 PM
I've suggested similar arrangements before... but here's a possibility, that should have very similar voicing to the Olympus, and occupy a relatively small "footprint".

The drivers used in this would be, per cabinet:

2- LE8/LE8T
1- LE175DTH/ LE85+HL87/ 2410+2305 / 2420+2305 (potato masher horn and driver)
1- 075 tweeter.

Crossovers should be at about 1200 Hz and 7000 Hz; at these frequencies, the drivers should still have good dispersion (even with the twin woofers). The LE8 is only just over 7" (cone of 6.75" at the outside of the surround), so two of these should be free from lobing/comb filtering at 1200 Hz, as long as the crossover slope is at least 12dB/oct.

Here's a pic of the setup, as I see it. You would probably have to have someone with modelling or measurement facilities do a crossover, since you would have a 4 ohm bass section (all the factory JBL units are made for 8 or 16 ohm low end drivers). Alternatively, a combination of JBL 3120 and 3105 could be made to work; the 3120 would need all INDUCTOR values HALVED (ie, 1/2 their original value), all CAP values DOUBLED and all RESISTOR values HALVED in JUST THE LOW PASS SECTION (for the LE8s), and it just might work without further mods. This would convert it for 4 ohm bass driver operation...

BTW: If you can find suitable alnico LE8 baskets, I can recone them into usable drivers for this project. It'll be using aftermarket parts, but I can "custom build" them for more-near "optimal" parameters in this situation...

John Y.
02-07-2005, 12:52 PM
Off axis cancellations is exactly what they do cause... that is the point. They are typically taking a wide dispersion dome and trying to limit their dispersion. Since we typically work with horns, the horn acting as a wave guide controls that for us.

As to what frequency to lessen the effect? Not sure. Certainly the lower the better. For JBL's Hercules system they use a pair of 10s up to 800Hz mating with the H9800 horn and they have deemed that acceptable.

Widget

Mr. Widget,

Ah, then, a horn loaded pair of woof/mid should work well to reduce the LF dispersion. Do yoy remember my concept of a Centregon with a pair of twelve inchers concentrating the lows over the curved panel (sort of a horn) and the HF projected from a single 2397? Think that would work to minimize the lobing? Or would it just make it worse? I'd like your opinion.

Thanks, John

Mr. Widget
02-07-2005, 01:10 PM
I actually have no idea what sort of sound would emanate from your centragon... I have noticed that in my home theater the 40X90 horns that I use seem to work well with film. The super wide dispersion of the 2397 may make image localization more diffuse. I am really only speculating here. I suppose the room you use (size and reflectivity) will have a huge impact here.


I say build the damn thing and let us know how it works... I imagine it will look so cool, that if there are acoustic short comings you won't care. This effect kept the Paragon in production for decades. :)

Widget

Steve Gonzales
02-11-2005, 12:44 AM
I suggested K110's , H91/l91/LE85's and a Slot (2405/077) earlier and here is my reason. You can't get too big so, a 10" driver that works well in a smallish enclosure is the best compromise. The K110 is not just an instrument driver. It has wonderful bass/midbass qualities that are important to the centerchannel because of the dialogue it handles. This driver also has enough LF ability to handle the huge dynamic range modern digital soundtracks have. The K110 could play well past the 1200hz mid crossover point and I believe it will blend naturally with the LE85/H91/L91 combo. I love the 076's absolute smoothness for the UHF duties, but are you going to find one? So, the 077/2405 is the next logical choice. It is VERY smooth on top and will also blend nicely with the other drivers-AND look cool too. If you are using a DD or DTS capable processer, then you're going to have good bass management control right?. This allows for a 70-80hz LF cut-off/crossover point so no worries there too. IMHO, an 8" driver is too small to keep up with the SR8's and a 12" driver(s), while better, require too much airspace to take full advantage unless you go with the 2202. So, That is my take, in full. I really like these type of discussions and welcome anyone to agree or be critical about my choice, that's how I learn too. I hope this is some food for thought. Thank you for letting me take part.

Alex Lancaster
02-11-2005, 08:34 AM
:) How about a 4612OK?

hosee
02-11-2005, 02:50 PM
I had the same problem trying to configure a center channel to match the left and right speakers. I built a 2 cu box and installed a reconed 2202, 2440, and 2405 which matched the components in the top half of the left and right speakers. I placed it on top of the television angled slightly down and it has worked good. It is tri-amped with a couple of Alesis amps and active crossovers. Some say that a properly set up system does not require a center channel, which may be true, however I have enjoyed mine and think it improved the overall sound even though my space is not ideal. The previous center channel was overpowered by the other speakers. I could try to send a picture if you were interested ( I would have to learn how to post it).

Mr. Widget
02-11-2005, 02:54 PM
Please do post a pic or two.

The center channel isn't necessary if you sit in the sweet spot and don't watch movies with friends. If there are more than two of you, a good center will make a huge improvement.

Do you think you are getting enough output below 200Hz from that 2202?

Widget

hosee
02-11-2005, 05:06 PM
So far I am satisfied with the range of the 2202. When I purchased the 2202, it had a non-JBL cone installed which had very poor range. I had it reconed with a JBL cone and the motor checked for alignment, etc and it is much better at the lower frequencies. It has the same components as the left and right and the same crossover frequencies and the sound match is pretty good. I will try to learn how to post a picture.