bi-amping XPL200; but how?

[soldier]

Hello,
I'm new to this forum and I found this forum because I wanted to sell my XPL 200's and looked around for a reasonable marketprice. But reading this forum I found out that I seem to be in the possesion of something special...;)

I bought my speakers 15 years ago, on telephone, while I was on an exercise, so without much listening and comparisations with other speakers. That came only afterwards and I was confirmed in the decision to keep them. But for two months my wife started urging me to get rid of these big speakers because we moved to another house. So I went to the local audio dealer and had them checked in order to sell them (which costed me 400 euro b.t.w.) But when they came back I couldn't resist to compare them with the best what the dealer had to offer. I expected that my XPL's would be no match for the big B&W's, Thiels and Dynaudio's. That was what my dealer expected as well (allways willing to sell new speakers to me offcourse...). Now: we were both very surprised to find out that the JBL's outplayed the bigger speakers of the other brands easely. The dealer spent half his morning in amazement and bringing in several new speakers to compare in despair.
We both concluded that the XPL's won on dynamic's and an uncolored soundpicture. But the placing of the instruments and vocals in between the speakers could be a little better. We also found the high tones, allthough brilliantly clear and clean, maybe a bit too sharp (and therefor a bit tireing after a while)

Now instead of buying new smaller speakers, I want to stay with my XPL200's (sorry for my wife...), but I also want to make the best out of what I have. I read some postings that with a DX-1 and bi-amping an even better sound could be achieved. Now here is the question: How do I do this? Apart from acquiring a DX-1 (does somebody know somebody who wants to sell?) I like to know what I need to have more and do to get this better sound. Or is it not worth the effort?


Regards,
Pieter Soldaat
Netherlands

[Guido]

Hello Pieter,

nice to have you here.
I love to hear that your XPL200's smoked the fashion speakers of these days. Never trust the hifi magazines, they are all "influenced". Trust your ears.

Biamping is not too easy, as I doubt the DX1 is for sale ANYWHERE.
There was a thread covering this from Member "Pasadena" search for it.

You could aquaplas (coat) the dome MF and HF drivers to reduce the sharpness. Robh3606 did this. Contact him.

[Robh3606]

Hello Pieter

To do the Biamp correctly you need a DX-1 because of the unique voltage drives. They are very hard to find and if you do it may not have the plug in crossover cards. Having the cards is not an issue. I built some cards up and there is a thread with simplified schematics and the schematics of the DX-1 threads linked. Passadena may be selling a DX-1 so I would contact him through a PM. He has a pair of them and cards for both if I remember correctly.

I biamped my clones before I had my DX-1 with a JBL M552 2 way electronic active crossover. The result were good. The DX-1 was clearly better and the best choice if you can find one.

http://www.audioheritage.org/vbulletin/showthread.php?t=11024&highlight=dx-1

I will add a couple of links later.

Rob:)

[Ian Mackenzie]

Rob,

I think they are gone already. (I was disptach clerk)

The easiest route might be to contact Welbourne Labs and get them to make up a customised crossover.

[soldier]

`You could aquaplas (coat) the dome MF and HF drivers to reduce the sharpness. Robh3606 did this. Contact him.`

Thanks all so far.
Making a custumised crossover seems to be a lot of work and money. A quicker way could be the use of aquaplas as I understood from Guido. Rob, could you elaborate on that? Is it something that you could do yourself and does it refect to the titanium domes only?

And b.t.w. I thought the titanium domes were the unique selling point of the JBL 200's and nothing could be better than those titanium domes, but now there seems to be improvement possible: what exactly is amiss with these domes and what can be bettered with aquaplas?

Pieter.

[gerard]

Hello

I use the Xpl200 crossover with My 250 Ti clone ( yes I know Giskard told already this is not good but it works for me ! ).

1. I try the xpl200 Xover in mono amp : Very bad for my config
2. I try the xlp200 by wire bi amping passive : better
3. Then I try the Xpl200 Xover bi amping with an active Xover ( rane ) and the result is very very good for me ; you need to play with the switch on the Xover and it has to be set to bi amp and be very careful otherway you can blow your speakers .

regards

Gerard

[Don C]

I don't know why the aquaplas makes such a big difference, but it does. Looking at the response chart of the midrange dome I see some resonant peaks well above it's normal operating range. I suppose that these modes could be reduced by the aquaplas. But I don't have data, it's just a theory. It may have more to do with the time/energy response, IE, the driver settles sooner after an impulse with the aquaplas. I did notice that when JBL updated the speakers, making the 200A model, one of the changes was to lower the crossover point between the tweeter and the mid dome.
Here's the odd thing, after having the aquaplas applied to my midrange domes, my first impression was that the system's bass was better. I guess that the midrange was not calling attention to itself so much, making the bass more noticeable.