250ti with 904ti

[pdemondo]

I am loooking at purchasing a set of 904TI's to replace the 104Hs on the 250ti. Has anyone tried this? I am trying to get the 250's to match the
PC600 a little closer. Has anyone done any frequency response models
on such a modification of the 250?

[4313B]

Why not just sell the 250Ti's and replace them with PT800's?

http://audioheritage.org/vbulletin/showpost.php?p=29677

[pdemondo]

If the PT800 had the 205TI top end and looked like the 250TI , I would.

I may end up getting a set of PT800 someday, I just can't resist experimenting a little. If I could get a set of 908TIs, I would love to
swap them in too.

[4313B]

If I could get a set of 908TIs, I would love to
swap them in too.

Yep.

Order a pair. I did.

[JBLnsince1959]

Why not just sell the 250Ti's and replace them with PT800's?

http://audioheritage.org/vbulletin/showpost.php?p=29677

exactly....This is advise you can take to the bank.....

I'll go into a little more detail tho.

1.the crossover points are completely different and the 250 crossover is designed for it's transducers, so it wouldn't work well.
2. Even if you were a crossover genius like Giskard, As far as I can tell tech sheets for the 904Ti aren't available
3. Also, the designer of both systems strongly advises not to do this

and even if you did over come the crossover problem, I can't see where it would come close to matching the PC600.

best solution is to live with it or get PT800 and PS1400 stacks


take care

[JBLnsince1959]

If the PT800 had the 205TI top end and looked like the 250TI , I would.

I may end up getting a set of PT800 someday, I just can't resist experimenting a little. If I could get a set of 908TIs, I would love to
swap them in too.

that's what I'm doing, however, I'm using the PT800 crossover design and not the 250's...it's an all or nothing thing. but just putting in the 904Ti won't work.

[4313B]

exactly....This is advise you can take to the bank.....

Yeah but after butting heads with a few guys and bouncing a few baseball bats off a couple heads over the last few years I've come to the conclusion that people will do whatever anyway as long as they maintain consciousness. And yes, G.T. would definitely say "won't work"

that's what I'm doing, however, I'm using the PT800 crossover design and not the 250's...it's an all or nothing thing. but just putting in the 904Ti won't work.

Nice! Could be cool.

[JBLnsince1959]

Yeah but after butting heads with a few guys and bouncing a few baseball bats off a couple heads over the last few years I've come to the conclusion that people will do whatever anyway as long as they maintain consciousness..

, yes that's the truth...

And yes, G.T. would definitely say "won't work".

BIG TIME!!!

Could be cool.

Maybe, it's fun project that I can get out of any time if it doesn't work well. there's only one way to find out tho and that's just do it..

[pdemondo]

that's what I'm doing, however, I'm using the PT800 crossover design and not the 250's...it's an all or nothing thing. but just putting in the 904Ti won't work.

Are you using the 044TI or the PT800 HF Transducer? For the LF, are
you using the active crossover and separate amp?

I was hoping someone had the TI mids spec sheet. That would be kind
of difficult to get in the ballpark without any parameters.

That would leave open only the possibility of active crossover and triamping.

HF crossover to 044TI, mid freq to 904/908TI and LF to LE14H-1.

Using the PT800 cross for the 904/908TI. Probably still somewhat of
a hack job.

[pdemondo]

Yep.

Order a pair. I did.

Where did you get the 908TI's from? JBL online does not stock them.

[JBLnsince1959]

Are you using the 044TI or the PT800 HF Transducer?

I'm not using anything from the 250 ( well the box and thats' not going to remain the same), all trans are from my PS series stack( PT800 and PS1400). the thread where I discuss this is http://audioheritage.csdco.com/vbull...ad.php?t=12988

For the LF, are you using the active crossover and separate amp

first off, I'll be using the stuff from the PS1400 and see what numbers i get in the 4CU. from there we'll most definity be going active between the LE14-3 and 908Ti

I was hoping someone had the TI mids spec sheet. That would be kind
of difficult to get in the ballpark without any parameters.

yes, real bummer and I went all the way to top. Either they were a pain in ass to find or JBL's not giving it out. However, you can get the numbers the old fashion way..where there's a will...

Using the PT800 cross for the 904/908TI. Probably still somewhat of
a hack job.

Personally ( I mean no disrespect) I think the whole project would be a hack job. all I can say at this point is you would be mixing water and oil.....I won't say it can't be done, BUT, I really wouldn't advise it. There's better options and places to put your time and money.


Understand tho, what i'm doing is taking the entire PS series stack ( PT800, PS1400 crossover designs) and putting them into a 250 enclosure and see how it sounds. I may even reduce the 250 enclosure volumn to 2.5 CF..My project is just for fun, an intellectual challenge and curiosiy. I have no expectations of it sounding good nor do I need it to.

There are many reasons I wouldn't recommend what you are trying to do;1. Hard enough to get it working correctly if all you're talking about is the 250; 2. However, in your first post you said you wanted to get the 250's to match the PC600, this is something that I don't believe could happen. Maybe best to look for some PT800's cheap.

However, I would never tell anyone NOT to do something. If you plan on doing this, be sure to get the TMo25 tweeter and EOSwaveguide too. Also, the midbass and midrange sub-chambers will work fine.

good luck

[pdemondo]

The PT800s do seem to be very cheap. The set on ebay now is BIN 1250, not bad. I remember seeing a few PT800's off and on for sale on ebay.
I guess I only have 5 sets of JBLs, (and the PC600 center). I mean how upset could the wife be if I show up with another pair?

The PT800s do sound good. I heard the PT800s and PC600 at a store
in Phoenix a copule of years back. They were playing a D. Krall
concert. Those speakers did an amazing job on the female voice.

The PC600 (IMHO) is a killer of a center channel. The most impressive
single piece of the system.

[4313B]

The PC600 (IMHO) is a killer of a center channel. The most impressive single piece of the system.

There you go! Put five of those puppies around your head and a couple LE14H-3's at your feet and call it a day.