New JBL M2

[shoshaw]

The eleventh commandment?



When you "delete" the factory settings are they gone for good? It just seems like they would be a good place to start instead of just tuning by ear.

The factory settings are still alive and well in my amp. I can turn them on and off at will. Believe me, I understand the passion for keeping the factory settings. Whether I start with the factory EQ or with some other basis, I will use EQ to correct the anomalies I measure/hear and to implement a "house curve" that makes me smile. When I look at my final EQ and the factory settings, the basic differences are in the areas effected by the room. When I switch between factory EQ and my EQ, I hear the room effects. When I start with the M2 EQ and fix the room problems, the result us virtually indistinguishable from the EQ I made from scratch. It is clear that correcting a room with EQ can only make one listening position really great and others only better. That's OK for me. I reserve the sweet spot. At the end of the day, I'm not going to do much more in terms of treating my room. It's a place the kids play and the wife is comfortable. All in all, I like their company more than I like the relentless pursuit of audio nirvana. Thanks to all who have contributed.

All in all, the M2 is still way beyond my expectations. I couldn't be happier.

[jpw]

Some of JBL Synthesis home theater calibrations adhere to SMPTE curves, which are not flat. I believe there is a bass boost build in to a SMPTE curve. Perhaps somebody with more technical information than I have can post a SMPTE curve, and or confirm whether or not M2's, when EQ'd via JBL's processing and or instructions, are EQ'd to SMPTE rather than truly flat.

[Robh3606]

A curve they use for Sythesis systems has already been posted in this thread. The M2 are set flat with the factory curves. You put in your own room EQ.

Rob

[Robh3606]

Why don't you do a sanity check on your factory settings with the other DSP off? Take a measurement 1-2 meters from one of the M2 on axis to see what you get. By on axis I mean with the mic centered on the horn so the mic is looking right into the throat. What you are showing makes no sense. You should not have anywhere near that much HF roll-off with that system. You should also be realitively flat above 1K. If the settings are right at 1-2 meters you should get somethig like this or better.

Rob

[ivica]

Why don't you do a sanity check on your factory settings with the other DSP off? Take a measurement 1-2 meters from one of the M2 on axis to see what you get. By on axis I mean with the mic centered on the horn so the mic is looking right into the throat. What you are showing makes no sense. You should not have anywhere near that much HF roll-off with that system. You should also be realitively flat above 1K. If the settings are right at 1-2 meters you should get somethig like this or better.

Rob

Hi Robh3606,

May be, I do not understand well, but You have presented 476Mg driver response with PT-H1010 horn....

For M2 response ( driver D2430K ) I would expect quite different response without ANY DSPs EQs.

http://www.audioheritage.org/vbullet...l=1#post343108


BASS section has to be OFF, so that there would not be a kind of bass to VHF driver interaction, as was the case

http://www.audioheritage.org/vbullet...l=1#post360232

with the shoshaw data.

Reagrds
Ivica

[Robh3606]

Hi Robh3606,

May be, I do not understand well, but You have presented 476Mg driver response with PT-H1010 horn....

For M2 response ( driver D2430K ) I would expect quite different response without ANY DSPs EQs.

Hello ivica

I didn't ask for all the DSP to be off. I asked for the speakers with just the factory DSP settings only. Above 1K you should get response similar to your on axis response. Why is there all of that roll-off and why is the response so uneven?? It shouldn't be that way. I posted the other curve as a reference, his measured in room response should be very close or better at 1-2 meters.

Rob

[ivica]

Hello ivica

I didn't ask for all the DSP to be off. I asked for the speakers with just the factory DSP settings only. Above 1K you should get response similar to your on axis response. Why is there all of that roll-off and why is the response so uneven?? It shouldn't be that way. I posted the other curve as a reference, his measured in room response should be very close or better at 1-2 meters.

Rob

Hi Robh3606,

I understand now. I can agree that the "HF roll-off " should not to be so large.
It behaved as WG without WG compensation....

Reagrads
ivica

[shoshaw]

Hi Robh3606,

I understand now. I can agree that the "HF roll-off " should not to be so large.
It behaved as WG without WG compensation....

Reagrads
ivica

The curve referenced below is the M2 with NO EQ. Incidentally, the factory EQ has about 9dB of HF boost to compensate for the roll-off you see.

Here is the M2 with the factory EQ measured at throat height at 1M. Indeed, the high end is nice and flat if you ignore the bump at 10k.

[Jakob]

It would be nice to get more information about crossovers: what kind of slope and at what frequency?

[ivica]

It would be nice to get more information about crossovers: what kind of slope and at what frequency?

Hi Jakob,

May be some info can be find in the our member's 4313B [ http://www.audioheritage.org/vbullet...r.php?15-4313B ] precious work:

http://www.audioheritage.org/vbullet...l=1#post354289

http://www.audioheritage.org/vbullet...l=1#post354296


http://www.audioheritage.org/vbullet...l=1#post354372
http://www.audioheritage.org/vbullet...l=1#post354340
http://www.audioheritage.org/vbullet...l=1#post354303

Regards
Ivica

[Jakob]

Thank you for those valuable links Ivica!

I'm a bit confused though when it comes to the PEQ. Most common type used is a 6dB slope, shelfs is only used once per driver. Whats the background to that fact?
How can you determine from the table in which way the 6dB slope's tilts?

Regards,

Jakob