Thanks for the info. I saw that SF-1 on QSC website costs only 150$. We have 4645C subwoofer, why it wasn't installed a B6 configuration????

I can't speak to other designer's or installer's methods. I do find that the majority of people tend to install stuff without really knowing what they are doing but rely on and/or copying what other have done. There is also the cost factor...often one can loose a sale to another simply because one was cheaper...the fact the end-user gets less is of no consequence. After all, the system worked when it went in, to some degree.

Glenn, what have you been doing with your drivers from your subs? I'm amazed by the amount of people that have never heard of reconing. When a speaker fails, it often can be repaired as good as or better than new. For instance, the 2242HPL driver used in the 4645B costs less than 30% to recone as to buy a new driver. There is NO difference between a reconed unit and the new unit. A driver recone basically keeps the frame and magnet structure and all of the rest is replaced with brand new components so all of the wearables are replaced.

E-mail me if you are interested in having your speakers reconed (or replacement diaphragms for that matter on Altec, EV or JBL).

Steve

I agree with you but... what about THX? As I said it is a THX theater and I have the original projects. There are no Subbass filters in the needed equipment.

As to THX...I don't believe that THX would have a problem with the B6 filter as it would extend the bass response of the system. You can always ask them before doing it. To my way of thinking, if a speaker designer tuned their box to the B6 specifications (part of that whole Thiele-Small thing) then to not apply the complementary filter to the signal is to have an incomplete system. Kinda like encoding with Dolby NR but not decoding with Dolby NR.

Steve

Now that I know what is B6 I agree with you that a filter has to be installed with B& compatibile speakers.
THX: Do you mean that THX will not "force" a B6 setup with 4645 and others b6 compatibile speakers???
On the THX's specs sheet I have there are wrote type and numbers of speakers, type and numbers of amps that has to be used for that cinema. Why does THX didn't write two B6 filters??

You are asking me to try and figure out why THX does or does not do things? You are joking. Right?

Steve

I will get back to you on the re -coning you mentioned. Im currently with UA and im part of the big mereger right now so im still uncertain about what Regal's procedures are for getting things repaired but im gonna mention it to the regional tech who is coming through to look at his new theatres. If we where still UA id get them fixed but stuff has been kinda on hold since the the whole merger started.

Looking at the old JBL sheets...the MPX line of amplifiers did NOT accept modules...only the MPA line did...sorry. To the looks of it, the MPX feels like the legacy line of CX amplifiers. Had you had the MPA line, then the IM-11 module would be the subwoofer module. Not to worry though, there are other means, like the RDL device.

Steve

Thanks! It's funny, I've wrote to QSC and answered me that MPX600 is similar to MX1500a so "perhaps" it should accept SF-1!

Since I didn't found any data sheet on JBL MPX amp, I trust you!

Thanks again for your time!

P.S. I found RDL filter you said at 89$. HOW can someone think to not install it with capable subwoofers????????
Also: I downloaded the PDF data specs. I saw that RDL make a boost of +5.5dB on 32Hz for 4645B. But... I never saw the frequency response of a 4645B without EQ. Shouldn't freq. response has to be flat?
How will be the final freq response of the 4645B with Dolby EQ + Boost filter?

Bye
Antonio

We are looking for someone to take care of are blown drivers also.

Look at the JBL 4645B (or C) data sheet. It shows it's response with and without the filter. That should answer your question.

Glenn:

The USA line of amplifier was NOT a replacement of the Series 1 (eg 1400, 1700) but a lower cost, stripped down version. The USA line basically was the same amp though (internally). The USA line did not offer the octal plug in ports to use accessory items but the later generation of USA amps did have Neutrix "combo" jacks that were nice.

The USA-1300 would not be my first choice for you since it was probably QSC's most failure prone amplifier (sorry to say). It was eventually replaced by a nearly identical looking USA-1310. A USA-1300 or 1310 with four 4645 subs would work fine. (two per channel). I have never been a big fan of running either the USA or series 1 amps into 2-Ohm loads (4-ohm bridged) though they are rated to do it...they will run HOT.

It seems though that you are moving in the right direction though.

Steve

Yes, I saw the pdf and I finally understood what "WITH EQ" and "WITHOUT EQ" mean!! Thanks

However you told that 4242A does not support B6 setting. But on specs I saw that there is the same "with eq" and "without eq"... What does it means?

If 4645C freq. response w/o the filter is as declared I wonder why JBL doesn't sell the filter with the sub...

Final question: why "B6"? What does it means?

I've heard that the Mx3000a and the EX 4000 are the same thing but different front, but then I heard from another source that the Mx3000a is a scaled down version of the EX4000.