AVS Forum banner

421 - 440 of 696 Posts

·
Registered
Joined
·
4,466 Posts
take off the smoothing. It's a lot more revealing. It will help you get it better. Smoothing is like makeup- less is more.
all it reveals is that a room has reflections. A default REW sweep in a room is completely unusable for a full range measurement. Variable smoothing in REW is too smooth IMV so if you want a listening position measurement then better to use Holm to get access to frequency dependent windowing.
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #424
Dude that is steeper house curve than even mine! We start trailing up about the same area, but I peaked out at 15dB hot where you are surpassing that pretty handily :)
I do need to tame the 25hz region slightly, but not much more for my listening tastes.

By 40hz I'm only ~12db hot, but then it takes off below that. That's what I like though, and is pretty much the same curve with the subs on.

These "full range towers" have some pretty crazy output down to 20hz.

These have such potent mid-bass that I'm crossing them with the subs at 100hz. Any lower and they're boosting 50-60hz way too much.
 

·
Registered
Joined
·
1,518 Posts
The posted curve

+

I do need to tame the 25hz region slightly, but not much more for my listening tastes.

By 40hz I'm only ~12db hot, but then it takes off below that. That's what I like though, and is pretty much the same curve with the subs on.
Makes me understand why you bother with the GHs at all. It is very interesting to see what others are intentionally EQing in their systems.

I also would like to see the unsmoothed graphs if you have them for the full range response.
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #426
The posted curve

+



Makes me understand why you bother with the GHs at all. It is very interesting to see what others are intentionally EQing in their systems.

I also would like to see the unsmoothed graphs if you have them for the full range response.
I should clarity. With the subs on, the curve continues on that same upward path and starts to roll off below 15hz :)
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #428
You NEED 6x more GHs if that is your actual curve for music/movies...:p
I boost the G's an additional 10db, and sometimes even a few more DB, for a demo every now and then...

Here are some SPL numbers from a recent demo for @Rowan611

Dubstep music: 138.3db at 28hz
EOT: 137.2db at 20hz
Pulse: 137.4db at 17hz
FOTP: Continuous 137db during the entire barrel roll
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #430
Ok when I'm there to visit, please don't subject me to that kind of abuse :p
Ha, that type of SPL is by request only, and ear plugs are always available!
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #433
Is that a continuous or peak measurement? What mic/software did you use to measure it?
That particular track maintains the same frequency for 2-3 seconds at a time. All of those SPL numbers were without clipping, but were very close to the limits.

MIC is a SPL Lab USB meter (Term Lab clone). Good up to 183b from 10-120hz.
 

·
Registered
Joined
·
21,319 Posts
one thing that you may wish to experiment with is taking a close mic of the woofer and the horn separately, then eq'ing those responses to be reasonably flat around the crossover region, then adjust levels and apply the crossover filter. from there, flip polarity and adjust delay until you get the big suckout at the crossover point, then flip polarity back. iirc, @mtg90 has worked with that horn/driver and created a very good looking response. he may have some eq advice/settings that may be difficult to see in the non-windowed response measurements taken indoors for the horn section.
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #435
one thing that you may wish to experiment with is taking a close mic of the woofer and the horn separately, then eq'ing those responses to be reasonably flat around the crossover region, then adjust levels and apply the crossover filter. from there, flip polarity and adjust delay until you get the big suckout at the crossover point, then flip polarity back. iirc, @mtg90 has worked with that horn/driver and created a very good looking response. he may have some eq advice/settings that may be difficult to see in the non-windowed response measurements taken indoors for the horn section.
Not a bad idea at all.

I did start with the MIC only about 2ft from the wave guide, and I was expecting to need a least a tiny bit of delay on the woofers, but adding any at all, even 0.02 ms, resulted in less SPL in the crossover region.
 

·
Registered
Joined
·
6,980 Posts
Not a bad idea at all.

I did start with the MIC only about 2ft from the wave guide, and I was expecting to need a least a tiny bit of delay on the woofers, but adding any at all, even 0.02 ms, resulted in less SPL in the crossover region.
The near field on the woofer will be helpful, but lower than observed the higher you get in frequency. You will get interesting and somewhat useful measurements at 2', but from a 2' wide horn you will see change in response shape as you move to at least 6' away, and I'd want to be at least 10' away, which is much more of a driveway project than in-room. There are some tricks you can do with boundaries by placing the mic against the ceiling, wall or floor which can give very good results under 5-10kHz which you can then splice with narrow gated measurements at mid-height in the room.

I wouldn't get too caught up with the delay, as most forget that any low pass filter has group delay, and if you want more you can just go to a steeper slope. There likely are some delay settings which would better match the midband of the woofer to that of the horn, but you would have to first set that and then change up the crossover type to work with the new time offset.

As you're finding, it's easy to make it function, but much more involved to feel like you have it really dialed in.
 

·
Registered
Joined
·
3,799 Posts
Discussion Starter #437
Might be worth padding down the tweeter so you don't have to attenuate it digitally so much. Just a thought.
At this point I think I need to to reach the noise floor I'm after.

I got the LG today, and it has pretty low noise floor. Not quite as low as the Crest CC series (no built-in DSP), but WAY lower than the MiniDSP. Although, at the seats I can still barely hear the hiss.

So, either way I've tried this, I still have a slight hiss at the LP, but I'm definitely sticking with the LG.

Can you throw me a link to a resister on parts express I should try?

I need to lower the gains on the LG by 28db to level match with the MBMs...
 

·
Registered
Joined
·
7,989 Posts
Isn't there a passive XO to blend the MF and HF pieces of that coax? That could probably be modified.

Resistors are cheap. I'd just buy the higher wattage ones and get: 2, 4, 6, and 8. Then arrange them in different Lpads like

Most attenuation

---8---!---DRIVER
!
2
!
Negative

To least attenuation

-----2----!----DRIVER
!
8
!
NEGATIVE


The first would offer the most attenuation and the second the least. I'd try something like a 4 and 4 and see what hat gets you. If you put in the Lpad and find you need to use boosts in your eq, raise it up to say a 2 and 6 or a 4 and 6. You really can't make a mistake with those resistors. Even if you use a 2 and 2 Lpad the impedance would still be safe for that amp, though I'd recommend a 2 and 4 as a minimum. If your worried about dropping the impedance to much just run it by me.

As for measurements. Isn't the MF and HF already worked out? So you just need to get the low blend right. I would think about the driveway if I were you. In your room getting useful results at 400hz is unlikely. You could use "at the seat" measurements. Normally I dismiss those as they're not representative for XOers in the midrange, but down that low it's all about the power response and getting it smooth at the seat is actually the point. Still important to know the anechoic response though. We could do it in July if you'd like.
 
421 - 440 of 696 Posts
Top