New JBL M2

[shoshaw]

[QUOTE=Bobecca;360139]

Do you have something to show that back this up??
Multiple subs will maybe even the freq response but removing resonances, well I dont think so!

OP wanted to have resonances in his listening experience, I wonder why? It is afterall the energy from the sub one wants to hear and not together with resonance caused by room boundary that interfere with the sub.
If that would be the case then why putting effort to treat those bad resonances in our small rooms.

Just saying

So, I have spent the day with a microphone and huge piles of Roxul. I piled Roxul, 11 inches thick, from floor to ceiling against the wall behind my speakers and found that it helped my bass response quite a bit. I also found those first reflections and treated them with 3.5" Roxul panels on the side walls. Tomorrow, I will look at the ceiling.

Interestingly, taking out those first reflections had little effect on the actual measured frequency response.

After further tweaking tomorrow, I will post measurements. In terms of turning on DSP, that's exactly what I've been doing all this time. I've been using the EQ to tune the system in my room. In my room, most of the factory EQ settings are not helping. In fact, if I left them in, I would simply be undoing them with more EQ. You guys are going to hate this but still the best response and sound so far is when I use my own EQ. Fire away...

[Robh3606]

You guys are going to hate this but still the best response and sound so far is when I use my own EQ. Fire away...

I don't understand why you need all that much EQ. Above the schrouder frequncy say 300-400 hz you shouldn't need much except posiibly a tilt cut to slightly roll off the highs if you feel you need it. They should be room friendly out of the box with their uniform off axis response. I could see a couple of filters for the primary room modes but not much else needed unless your room is a real bear.

Rob

[audiomagnate]

[QUOTE=Bobecca;360139]

Do you have something to show that back this up??

http://www.harman.com/EN-US/OurCompa...itePapers.aspx

[Bobecca]

[QUOTE=audiomagnate;360161]

http://www.harman.com/EN-US/OurCompa...itePapers.aspx

I've read this before. But there is nothing there that shows that resonance caused by the room is reduced by EQ. I cant find any waterfall plots that backs up what you imply, not yet at least. The only thing that is shown is that one can EQ out response by using multiple subs, and I dont see any harm by doing that any way

Interferance causing a dip in the freq response cant be solved by EQ, but I have solved my dips with tuned helmholtz resonator. And these devices will also reduce resonances and shorten the reverberation in the low end. I get so many beneficial aspects with treating a room then go with the route of EQ.

When the room is fixed then I can apply the EQ for a room curve as needed for my taste. And that is a big difference. I dont remove the setting that is there for the speakers.

[Robh3606]

Here is what the JBL Synthesis curve look like. The Revel sub software has the same elevated level for their optimum in-room curve as well. You can see the tilt EQ on the top end. You should easilly be able to come up with single tilt eq setting and the bass is self explanatory.

Rob

[audiomagnate]

What's the reason for the 10 dB downward slide in the top octave?

[Robh3606]

That's a 5db slide the 100-1K is the flat area with a 5db bass rise. That is their, or one of their target curves. If you go flat in the bass it sounds lean and if you go flat on the high end it sounds bright. So they put in bass fill and rolled of the top end a bit. I have a similar curve on my HT mains but I dont roll off the highend as much and my hinge is further out. Here is a measurement curve from a Revel Performa F208. Look at the predicted room response curve. See any similarity??

Rob

[Audiobeer]

I wonder how the specs compare to my favorite 2 ways the 4430's?

[shoshaw]

Hi Everyone. As promised, here is some data I collected over the weekend.

First graph shows the before (green) and after (blue) of placing 12" of Roxul in the room corner behind the speaker. Pretty dramatic improvement in the 70Hz range. Problem is not gone but it's way better.

Second graph shows the M2 with factory crossovers only (EQ deleted). Purple is without Roxul. Blue is with Roxul in the corners and placed to absorb first reflections from the side wall and ceiling.

In spite of the room treatments, I still cannot eliminate the peaks between 500-1kHz I detect in the M2 factory EQ in my room. The good news is that a touch of EQ makes it all better.









[QUOTE=shoshaw;360141]

So, I have spent the day with a microphone and huge piles of Roxul. I piled Roxul, 11 inches thick, from floor to ceiling against the wall behind my speakers and found that it helped my bass response quite a bit. I also found those first reflections and treated them with 3.5" Roxul panels on the side walls. Tomorrow, I will look at the ceiling.

Interestingly, taking out those first reflections had little effect on the actual measured frequency response.

After further tweaking tomorrow, I will post measurements. In terms of turning on DSP, that's exactly what I've been doing all this time. I've been using the EQ to tune the system in my room. In my room, most of the factory EQ settings are not helping. In fact, if I left them in, I would simply be undoing them with more EQ. You guys are going to hate this but still the best response and sound so far is when I use my own EQ. Fire away...

[Mctwins]

[QUOTE=shoshaw;360232]Hi Everyone. As promised, here is some data I collected over the weekend.

First graph shows the before (green) and after (blue) of placing 12" of Roxul in the room corner behind the speaker. Pretty dramatic improvement in the 70Hz range. Problem is not gone but it's way better.

Second graph shows the M2 with factory crossovers only (EQ deleted). Purple is without Roxul. Blue is with Roxul in the corners and placed to absorb first reflections from the side wall and ceiling.

In spite of the room treatments, I still cannot eliminate the peaks between 500-1kHz I detect in the M2 factory EQ in my room. The good news is that a touch of EQ makes it all better.

I am confused regarding your measurement, this before and after roxull, is it with the EQ or??

I asume you are using Audio Architect to set you amps and speakers. Are you familiar with pre PEQ and post PEQ?

You still schould use the settings for the M2.

Remember, when measureing before and after it is important that the mic is exactly in the same position, the mic shall not be moved.

[audiomagnate]

the mic shall not be moved.

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.

[Mctwins]

Take a look here, removed all of my Roxull.

http://www.gearslutz.com/board/8325451-post113.html

and how it is tuned

http://www.gearslutz.com/board/8912421-post114.html

You will have a hard time to solve your bass issue in your room with pouros absorber(roxull). Been there done that.

Seeing your measurement at post39, there is little changes to have some effect. You must phase shift your pressure in the corners. The Varitunes do three things, that is Phase Shift, reduce Resonances and reduce the Decay Time.

[Bobecca]

shoshaw...

But if you move the mic to a diffrent pos does the change made by roxull still holds? Like Valentin mentioned earlier, measure in a diffrent pos, especially in the bass region!

Why the heavy drop of the higher freq?

Is it possible to show the impulse response when absorbers on the sides where installed?

Still want to emphesize that the setting for the speakers should be there. It is a part of the loudspeaker setting

[Bobecca]

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 problem is that it is the room that is causing the anomalies in the freq response not the speaker. The speaker measures flat in anechoic condition. That is why the settings must be there for the speakers.

[Robh3606]

The speaker measures flat in anechoic condition. That is why the settings must be there for the speakers.

Yes I couldn't agree more. At least that way you know the speaker is"right".

Rob