Need help with bass response

[boputnam]

When I switch the leads on the bass drivers only whereby + is + and - is -, the Phonic reads Not in phase. Does anybody else have this situation?

I'm starting to get confused...

I think what is confusing you - but I might be confused in what you are observing - is that when the cabinets are wired the way JBL intended, the woofers are opposite the polarity of the rest of the cabinet. This response is confusing the Phonic which is seeing the different polarity as "wrong". It is not wrong, it is correct by design.

I've not used the Phonic, but can you hold it RIGHT UP in the woofers to check only them, and then do likewise with the other transducers?

If you had the Galaxy Cricket, it would tell you the woofs are (-) and all the others are (+). That is good. That is what JBL designed for that network.

[invstbiker]

If this is the case, then all (neg) bass transducers need to be wired unconventionally to be in proper phase. That is the + lead to the - low frequency terminal. That's what my Phonic tells me anyway. I'm all IN PHASE now with this wiring. And it sounds DAMN good!

[Zilch]

If you go back to the original thread on this, I believe you'll find that that woofers are supposed to operate out-of-phase with the other drivers on the schematic. Follow the black leads there.

Why? Because JBL determined doing that produced the desired acoustic transitions between/among the drivers, in the context of their physical alignment and the passive crossover topology built into the system.

When biamping, you must make your own determination according to the differences that might be inherent in whatever external crossover you are using. Your RTA can help with this, but listening is the final determinant.

Read up on biamp phasing in the 5235 manual, for example....

[invstbiker]

I'm starting to get confused...

I think what is confusing you - but I might be confused in what you are observing - is that when the cabinets are wired the way JBL intended, the woofers are opposite the polarity of the rest of the cabinet. This response is confusing the Phonic which is seeing the different polarity as "wrong". It is not wrong, it is correct by design.

I've not used the Phonic, but can you hold it RIGHT UP in the woofers to check only them, and then do likewise with the other transducers?

If you had the Galaxy Cricket, it would tell you the woofs are (-) and all the others are (+). That is good. That is what JBL designed for that network.

NOW that makes sense, If this is JBLS's intention, then the Phonic SHOULD READ not in phase and is reading it correctly. PERFECT!! GEEZ. And Yes I can check Low end, High end, Left and right all separately. That's worth a drink right there. Thank you!! GEEZ I can finally end the 2 am thinking about this. Now it's happening!!

[invstbiker]

If you go back to the original thread on this, I believe you'll find that that woofers are supposed to operate out-of-phase with the other drivers on the schematic. Follow the black leads there.

Why? Because JBL determined doing that produced the desired acoustic transitions between/among the drivers, in the context of their physical alignment and the passive crossover topology built into the system.

When biamping, you must make your own determination according to the differences that might be inherent in whatever external crossover you are using. Your RTA can help with this, but listening is the final determinant.

Read up on biamp phasing in the 5235 manual, for example....

NOW it makes sense, just takes me a little longer....Thank You!!

[boputnam]

Yes I can check Low end, High end, Left and right all separately.

Good.

For the polarity test, use the Phonic up close - right at the transducer you are checking.

You should get:
UHF = (+)
HF = (+)
MF = (+)
LF = (-)

Man, if we finally got there, you should be very pleased with the bass response.

Zilch'ster - thanks for sticking with this!!

-----

One thing on the Ashly XR1001: the decal markings on the front are not very precise. On mine, I find that I need to set the frequency just a bit below what is marked on the face to be at the desired point. You could check this using your Phonic.

Mute the HF outputs on the Ashly. Using only the LF outputs, use the Phonic RTA. You will see the frequency response curve slope off. Dial the xover point slowly and watch the curve change. Listen, and watch the RTA - you may be able to pin-point the right setting. I don't know if the RTA's resolution is sufficient to really see what is going on, but maybe.

[invstbiker]

Good.

For the polarity test, use the Phonic up close - right at the transducer you are checking.

You should get:
UHF = (+)
HF = (+)
MF = (+)
LF = (-)

Man, if we finally got there, you should be very pleased with the bass response.

Zilch'ster - thanks for sticking with this!!

-----

One thing on the Ashly XR1001: the decal markings on the front are not very precise. On mine, I find that I need to set the frequency just a bit below what is marked on the face to be at the desired point. You could check this using your Phonic.

Mute the HF outputs on the Ashly. Using only the LF outputs, use the Phonic RTA. You will see the frequency response curve slope off. Dial the xover point slowly and watch the curve change. Listen, and watch the RTA - you may be able to pin-point the right setting. I don't know if the RTA's resolution is sufficient to really see what is going on, but maybe.

This is exactly what I have now. Thank God it's over whew. Now just enjoy the music..

[edgewound]

All through this exercise it's still important to know that all 4300/4400 series studio monitors and L-Series home speakers, with the exception of 4311 and 4312, are positive to black input terminal.

[invstbiker]

Why? Because JBL determined doing that produced the desired acoustic transitions between/among the drivers, in the context of their physical alignment and the passive crossover topology built into the system.

When biamping, you must make your own determination according to the differences that might be inherent in whatever external crossover you are using. Your RTA can help with this, but listening is the final determinant.

I just did several A/B comparisons with different pieces of material and I've gotta tell you, I get better bass response when the woofs are wired back asswards making it "IN PHASE" vs. out of phase with the other transducers. "listening is the final determinant" I agree...

[boputnam]

I get better bass response when the woofs are wired back asswards making it "IN PHASE" vs. out of phase with the other transducers. "listening is the final determinant" I agree...

With them wired that way, you are getting a doubling of the frequencies in the area of the crossover point between the LF and MF. I don't know the exact range, but guess it is between say 200Hz and 400Hz. The slope on the Ashly is -24dB, but I think the passive network is -12dB, so there could be a considerable area of summing.

If you like that, cool. However, you may find that while there is "more bass", it is not as distinct tonally as with the LF opposite. Keep us posted...

[boputnam]

...positive to black input terminal.

This got me thinking, invstbiker - you face one hell of a quandry.

Going with this, you'll get:

JBL spec
UHF = (-)
HF = (-)
MF = (-)
LF = (+)

invstbiker way
UHF = (-)
HF = (-)
MF = (-)
LF = (-)

The whole thing will suck. Your eyeballs will pop out of your head!

Remember what Giskard used to say - "it's all fun and games until someone loses an eye...!"

[invstbiker]

This got me thinking, invstbiker - you face one hell of a quandry.

Going with this, you'll get:

JBL spec
UHF = (-)
HF = (-)
MF = (-)
LF = (+)

invstbiker way
UHF = (-)
HF = (-)
MF = (-)
LF = (-)

The whole thing will suck. Your eyeballs will pop out of your head!

Remember what Giskard used to say - "it's all fun and games until someone loses an eye...!"

Correction, I have all

UHF = +
HF = +
MF = +
LF = +

The only difference is the LF. The JBL way has the LF = - when I switch this one only, I get it + thereby all are in phase, not out of phase. If I follow the Edgewound way, I get a better kick out of the LF

[boputnam]

Ah...

[Mr. Widget]

Bo asked me to merge the Phase thread with the Bass thread as they are a bit intertwined... hope this makes sense.


Widget

[invstbiker]

Bo asked me to merge the Phase thread with the Bass thread as they are a bit intertwined... hope this makes sense.
Widget

Perfectly