[HAM] Single louver horn compartment damping material?

[David Anderson]

On Apr 6, 2007, at 11:37 AM, OF wrote:

> At 08:30 AM 4/6/2007, John Doyle wrote:
>
>> What about swapping crossovers Alan?
>>
>> JD
>
> Would they be any different, John?

They very well might be, 50+ years after they were made. The  
crossover capacitors are paper, and they do drift in value and  
develop significantly higher dissipation factor as they age, which  
would have the same effect as putting a resistor in series with the  
capacitor. (However, the inductors used in the older Leslie  
crossovers are laminated steel, which is a superior technology  
compared to the later ferrite core inductors.) I've used GE  
Dielektrol VI capacitors to rebuild these crossovers with results  
very pleasing to my ears. I recommend rebuilding, not replacing these  
crossovers.

But I'd still put my bets on the effect of the damping material in  
the 21H, which, to re-emphasize my point, was simply something I  
brought up because I wasn't aware of it ever having been used in the  
first place, it having been removed from the two cabinets I have  
where it was originally installed. Lord knows other things that have  
far less effect on the final sound have been discussed at great  
length. I'm not for or against this stuff being in the horn  
compartment. I just wanted to know what it was and what effect it  
would have. The rest is up to one's own taste, but it's an easy and  
easily reversible experiment to try.

I had a long conversation last night with someone who knew Don Leslie  
well, and, in reference to this subject, he pointed out that Don's  
intentions for the Leslie sound were rather different than the uses  
they were adapted to by jazz, pop, and rock musicians, which goes  
without saying for Scott, but it was good for me to hear from someone  
close to the source and might prove useful to others.

David A.

>
>> ----- Original Message -----
>> From: "Alan Lenhoff"
>>
>> I'm in a pretty good position to do a controlled experiment: I've  
>> got a 21H
>> and a 31H, both with original woofers (Jensen field coils) and treble
>> drivers (V-21s). And both are powered by  21H amps in good condition.
>>
>>   Even if I switch the amps or treble drivers between the  
>> cabinets, the 31H
>> cabinet always sounds brighter (and louder, too
>