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XRT20 Speaker System Restoration (and questions)

w1jim said:
I've been playing my Telarc digital 1812 overture - the canons are just so intense!
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No no no... Pachelbel used canons. Tchaikowski used cannons. :)

The Telarc 1812 is a terrific torture test for speakers. I dubbed a cassette of that disc for my music history prof when I was a student, and when he played it for the class, it killed the speakers in the UF music building's choir room. :thmbsp:
 
Torture for speakers???? it was "easy" on speakers compared to what we needed to learn to do to allow a turntable and cartridge to track this monstrocity..
 
c_dk said:
Torture for speakers???? it was "easy" on speakers compared to what we needed to learn to do to allow a turntable and cartridge to track this monstrocity..
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Oh, you were dealing with the LP... I have the little shiny disc. :)
 
Well then, I guess my speakers have been cannonized.
After all, my wife does call it the alter of sound.
 
Scare up a copy of Cyrstal Clears direct to disc that contains a recording of "Fanfair for the Common Man". Introduced this Lp to Gordon for the XRTs midwest unveiling, he purchased a number of them to use thoughout the resr of the rollout thoughout the world.
 
mrz80 said:
No no no... Pachelbel used canons. Tchaikowski used cannons. :)

The Telarc 1812 is a terrific torture test for speakers. I dubbed a cassette of that disc for my music history prof when I was a student, and when he played it for the class, it killed the speakers in the UF music building's choir room. :thmbsp:
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I thought PacBell Canon was a gigabit switch out in the San Francisco bay area? :music:


-Gregory
 
Meanwhile back in the land of XRT20's I did have a problem which was finally resolved today.
One of the woofers in the higher frequency range had developed a voice coil rub which naturally resulted in a nasty buzz.
Since I had refoamed all of the drivers I suspected that one was misaligned. I refoamed it and paid particular attention to shimming the gap in the voice coil - but alas, it still rubbed. I decided that the voice coil was likely distorted or there was a piece of the coil that either came undone or was burnt.
I sent it to New Foam (www.newfoam.com) in Rochester NY, which I have seen mentioned as a good place to have these fixed.
Initially they thought that they could fix the existing VC and told me it would cost $40 (plus shipping) to repair. Ultimately it required a complete reconing and replacement of the VC - which normally would be more like $90 but they said that they would stick to the original quote despite the additional work.

Got it installed today and will proceed with the break-in process (and cannonization of course).



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w1jim said:
I sent it to New Foam (www.newfoam.com) in Rochester NY, which I have seen mentioned as a good place to have these fixed. Initially they thought that they could fix the existing VC and told me it would cost $40 (plus shipping) to repair. Ultimately it required a complete reconing and replacement of the VC - which normally would be more like $90 but they said that they would stick to the original quote despite the additional work.
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Sent my 12" XR6 woofers to Newfoam in NY on the advice of Roger Russell and they are working fine.


-Gregory
 
w1jim said:
Got it installed today and will proceed with the break-in process (and cannonization of course).
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Very nice work. :thmbsp: Once the wife tells me we are moving into the condo (on & off for several years now :dunno:) am hoping to find a set of XRTs. But, your cannonization may have to wait............ have read that the pope is quite ill.
 
w1jim said:
Here's an update - I found a reference on the Rodger-Russell site talking about the treatment used on the woofer surrounds:

The surround is still foam but a protective coating of diluted Airflex 400 was painted on the outside of the surround.

See the information under "12" Woofer 036-047" about midway down the page.
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I emailed Roger Russell about the Airflex 400 - here's his response:

Airflex was used on early surrounds because of the self-destruct tendency of polyurethane foam. The later polyether foam did not have this problem. My XR250s are 20 years old and the ether foam is fine so no coating is needed for new surrounds of ether.

The bass compensation was only needed for the ML and early XR systems and not the XRT systems. However, the filters in the 104 and 107 are still useful to combat room resonances.

JimB
 
w1jim said:
The bass compensation was only needed for the ML and early XR systems and not the XRT systems. However, the filters in the 104 and 107 are still useful to combat room resonances.[/I]

JimB
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That is certainly not what we measured in the field or what his own white paper states....(posted under Mac Tech sticky download pages 6-10)..can not think of any XRT system that did not need the 2 bass setting at the least...to get them to sound their best you need to get the woofers out of the corners so the corner effect is nulified.
 
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My XRT-20's had the 4 woofers and 2 mid-range's replaced by Audio Classics on an exchange basis. Part #'s matched the old one's and the "salad bowls" that were missing were also replaced, resealed with the proper putty and all re-installed.

These are later model 20's with the nice neat crossovers from 1989 IIRC, so I didn't replace the capacitors. Also, my tweeter columns are mounted on the outsides of the credenzas, to the left of the left and right of the right credenza. The mounting posts connecting the cabinets to the tweeter columns are installed and the curved feet on the tweeter columns are also in place. These are possibly the most mint set of XRT 20'S in existence.

My question is, should the tweeter columns be inside or outside the credenzas as I have them? Any modifications or placement suggestions you can offer. I have no set up or installation brochures to refer to and could never find instructions online to read or print out?

:music:

Thanks.

Oh yea, these speakers just love the MC-501's powering them. They love all the power and really take what you give them. I was thinking of adding a Mc 104 or 107 Eq as listed above or the MEN-220 Room Correction System with custom eq and 2 way crossover with built, in microphone and set up the room properly.

Philip
 
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On every one of the dozen or so we installed the columns went inside to meet the 1/3rd room division. If that did not work because of obstruction we used xr19s.

Once you have listened to a mq107 system properly setup, you will not want to ever give it up.
 
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You can contact Roger personally if you have any questions. Just go to his website for the address.
 
Remember that there are early arrival sounds that come directly from the speaker and are not overly influenced by the room and later sounds that are totally influenced by the room. By having the tall column of tweeters the influence of the room is reduced, but not eliminated. So if you measure the sound at the listening position depending on the qualities of the room you will be compromising the direct early sound to satisfy the later reflected sound of the room when adjusting your graphic EQ
The early sound is what tells your ear about locations of instruments,and width and depth of the presentation..

I get the best satisfaction by first balancing the system up to about 3,000 hz at the listening position, then check the emissions at 4 ft to see what has happened to the direct sound. I then touchup the the area from 400 to 20,000 hz, and go back to the listening position. Where I re-examine the final output. I usually have a few mid issues to compromise. I leave everything above 3000 hz alone, but make sure that spectrum integrates , balances, with the frequencies below. I build in a 6 to 8db roll off between 3,000 and 15,000 hz, that I can restore to flat with my tone controls on the pre-amp if necessary. I strive for a live performance sound and not a recording studio sound so popular to day.
 
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