How does cabinet size affect the sound of a speaker?

Captain Humble · « **on:** 5 May 2004, 01:08 am »

I need a center channel to match up with my Loreleis and thus far have found nothing.

I'm considering taking a full size Lorelei and chopping off the bottom so it is only 20 inches tall. The stock Lorelei is about 41 inches tall with the drivers near the top and the rear port at the bottom. There is a slight taper towards the top so there is a little less volume (cubic feet) in the top than in the bottom.

Can anyone predict what one could expect from such a radical modification?

Would it be a good match as a center with my Loreleis?

Would it play as loud as a stock Lorelei without blowing a driver?

Thanks,
Jeff

binarywhisper · « **Reply #1 on:** 5 May 2004, 02:31 am »

The Lorelei's that I have seen were 2 way TL's. The cabinet is a very carefully tuned part of the speaker. Cutting it will definitely have a dramatic effect on its sound.

You know if you are going to go though that much trouble you should consider building a center channel. By the time your done modifing you'll have pretty much built one anyway, it just won't be as good.

JohnR · « **Reply #2 on:** 5 May 2004, 02:31 am »

That might actually work, assuming that you seal the stumpy version. The bass will roll off a fair bit higher. I can do a guesstimate simulation if I know what woofer it is and the rest of the cabinet dimensions. I have a feeling it's the Scanspeak 21W/8545?

However it seems like a rather expensive way to go. Surelymust be a suitable center channel in existence already - ?!.

Captain Humble · « **Reply #3 on:** 6 May 2004, 02:07 pm »

Thanks for the responses.

BinaryWhisper

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The Lorelei's that I have seen were 2 way TL's. The cabinet is a very carefully tuned part of the speaker. Cutting it will definitely have a dramatic effect on its sound.

I was afraid of that.
What does TL's stand for?

John R

Quote

That might actually work, assuming that you seal the stumpy version. The bass will roll off a fair bit higher. I can do a guesstimate simulation if I know what woofer it is and the rest of the cabinet dimensions. I have a feeling it's the Scanspeak 21W/8545?

Scan-Speak 18W/8545 midwoofer.

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However it seems like a rather expensive way to go. Surelymust be a suitable center channel in existence already - ?!.

My intent was to ask Klaus to build the Lorelei center. It should be easy for Alan to take the Lorelei plans and simply shorten the speaker by eliminating x number of inches from the top. Since the speaker is tappered taking the length from the top would maximize the amount of cubic feet left in the cabinet. My goal was to employ a center that had the same drivers and crossovers as the mains in the hopes of obtaining a great timbre match across the front while not having to baby the center from an SPL standpoint.

Since I have no background in speaker design, I'm concerned about changing the volume of the cabinet and secondly the Lorelei is ported lower back. This mod will put the port partially behind the midwoofer.

My preference would be to purchase a stock center that fits in my space that I can drive hard and matches well with the Loreleis. Just haven't been able to find one yet.

JohnR · « **Reply #4 on:** 6 May 2004, 02:34 pm »

TL = transmission line. Here's an example, the Lorelei won't be the same as this inside but you can see why cutting in it in half might not be such a great idea:

http://www.t-linespeakers.org/projects/jakob/index.html

Assuming you did it and the internal volume of the half-pint was 15 liters, you could either seal it with an f3 around 90 Hz or tune the port for an f3 around 45 Hz.

Marbles · « **Reply #5 on:** 6 May 2004, 02:43 pm »

Have you spoken to Klaus yet about the possibility to have a center channel made for you?

What did he say?

byteme · « **Reply #6 on:** 6 May 2004, 02:48 pm »

John,

The Lorelie isn't a transmission line design. It's pretty wide open on the indside,

It's a little hard to see in this picture, but if you look past the crossover it's wide open all the way up to the drivers...

So what Jeff wants to do SHOULD work, but that crossover is so big that it would have to be either mounted differently OR you'd have to cut the cabinet size down from the top rather than coming up from the bottom.

Marbles · « **Reply #7 on:** 6 May 2004, 03:08 pm »

How did you feel the nOrh 9.0 matched up as a center?

Just curious because if you crossed that speaker over to a sub at 80 hz, it could play as loud as the Lorelies (full range).

I had mine XO at 80 hz and had no problem playing above reference levels in a fairly large room.

Captain Humble · « **Reply #8 on:** 6 May 2004, 05:30 pm »

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Marbles:
Have you spoken to Klaus yet about the possibility to have a center channel made for you?

Yes, as a matter fact he offered to do so without my asking when we determined that the Nemesis wouldn't work for me. He's still as gracious and accomadating as ever.

Klaus has publicly stated that he isn't a designer. That's why I was looking for opinions regarding chopping down a Lorelei before I asked him to do it. And I do agree with the rest of you that this would be a last option after exploring existing center channels on the market.

Regarding the Marble 9.0, tonnaly it was a very good match just as you predicted prior to my purchase of the Lors. But, even crossed at 80 I found it wanting from an SPL standpoint. Case in point, HELL FREEZES OVER CD, HOTEL CA. I crank it to enjoy the beauty of Walsh's nylon string solo intro then, BANG here come the drums and IMHO the 9.0 just isn't designed to deal with it. As you probably recall I had 3 marble 9.0s at one point and blew midwoofers twice. They were all crossed at 80. On the other hand, the Loreleis running full range don't even break a sweat.

Byteme,
Thanks for the pics and advice. If you read my post above I was planning on chopping the top off.

FYI:
I'm now chasing a lead on a center that appears to have great potential.

I'll keep y'all posted.

Thanks for the input.

Jeff

Marbles · « **Reply #9 on:** 6 May 2004, 05:49 pm »

HOLY CRAP! you must REALLY (and I mean REALLY) like those high spl's!

Anyway, you might actually be doing Klaus a favor by having him make you a center channel. It would be another NEEDED product for his line up.

byteme · « **Reply #10 on:** 6 May 2004, 05:55 pm »

Quote from: Marbles

HOLY CRAP! you must REALLY (and I mean REALLY) like those high spl's!

Anyway, you might actually be doing Klaus a favor by having him make you a center channel. It would be another NEEDED product for his line up.

He's got a big honkin' room to fill with noise! High ceiling, a couple door openings, plenty of soft stuff to absorb sound. When I was there we had it pretty loud and the Lorelei's never broke a sweat but I could see something lesser puking!

Captain Humble · « **Reply #11 on:** 6 May 2004, 06:12 pm »

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byteme said: He's got a big honkin' room to fill with noise! High ceiling, a couple door openings, plenty of soft stuff to absorb sound. When I was there we had it pretty loud and the Lorelei's never broke a sweat but I could see something lesser puking!

Thanks for the backup byteme.

I was just heading for the door to get my hearing checked.

Captain Humble · « **Reply #12 on:** 6 May 2004, 06:27 pm »

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marbles wrote: Anyway, you might actually be doing Klaus a favor by having him make you a center channel. It would be another NEEDED product for his line up.

Marbles, I couldn't agree more. Were Klaus to invest a little R&D money in this project a failure would only result in the loss of a half a cabinet while a winner would complete his Lorelei offering. Of course I'm assuming there are no contractual issues with Symphonic Line but were I them, I'd want to sell all the crossovers I could.

Had there been such a center when I purchased my pair I would have jumped on it. My bet is that byteme and satfrat would have as well.

byteme · « **Reply #13 on:** 6 May 2004, 06:49 pm »

True, Jeff, in fact I did try the Nemesis but it just won't do it for me. I want more impact from the center and the Usher 616 looks to be the ticket for me. Beautifully made, excellent drivers, quality components and I'm sure once it's run in will be an excellent peformer.