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Discussion Starter #1
I'm putting aside my 15hz tuned box for awhile and plan to build a box that will offer a bit more mid-bass "slam".

I'd like for it to be a ported build. I have a 3500 cu. ft. room that opens up to a medium sized kitchen, which makes the room even bigger. And I've struggled with the loss of midbass slam. So I want to accentuate this area as much as possible.

Do you recommend something like a 30hz tune?

Eventually I'm going to get crazy with room treatments, but I'm trying to remodel my house and this is not a good time for these projects.
 

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No, I personally don't.

Before you begin this chase, have you taken a FR measurement at your seat? 10 to 1 odds that the problem is not the sub tuning, but rather the sub placement, seat placement, or sub distance setting in the processor.
 

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Discussion Starter #4
As I eluded to in my first post (but apparently not strongly enough), my problem is likely due to my room.

And sorry, I was wrong about my current tune. I've got one eD 190v.2 in a 13 cu. ft. box tuned to 18 hz with an 8 inch port. Both the woofer & port are downfiring. And I've also tried the box on it's side.

I've tried in two corners on opposite ends of my room, as well as a few spots in between. My box can deliver some frighteningly scary low "thuds" at high SPL.
But it lacks the "slam" that I enjoyed a couple years ago with a sealed mid-Q Tempest subwoofer in a more boxed-in room than I have now.

I use Audyssey MultEQ XT for equalization. I had the same problem with my last build in this room, an SBB4 Tempest.

So like I said earlier, I want to "accentuate" the mid-bass area. What tune do you recommend for this?
 

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As I eluded to in my first post (but apparently not strongly enough), my problem is likely due to my room.
I'm not an expert, but my understanding is if the current problem is your room, (more specifically, room modes), no tune will help. You need to move something, sub, seating, or room. If your listening position is in a null at the frequencies you want, it cannot be overcome with a different tune or equalization.

When you did have the "slam" you wanted, were you still using the same mains? Where are you crossed over at? What equipment do you have? Have you done a FR plot of the sub by itself, and with the mains?

We're trying to save you the trouble of building a sub with a different (higher) tune, and ending up with the same basic results, except that now the really low thuds are gone, too. If you just want to build another sub 'cause you have the itch, then by all means, go for it.
 

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So like I said earlier, I want to "accentuate" the mid-bass area. What tune do you recommend for this?
That has little to do with the extreme LF or the bottom end tuning. It has everything to do with room placement and integration.

Another possibility is that your system is just fine but you prefer some emphasized kick.

Either way, no need to build a new sub.

Kal
 

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Take 30 minutes to bring a computer into your room and do a FR sweep with RoomEQ Wizard, that will tell you almost everything you need to know.

I use Audyssey MultEQ XT for equalization
This could be a big part of the problem too, but you'll never know until you take some measurements.
 

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Discussion Starter #8
Kal, it certainly could be me I suppose. I had a Logitech Z-5500 subwoofer in here for awhile, that exaggerated the mid-bass and I did enjoy that kick that it had. It didn't get nearly as loud as the last two subwoofers I've built. Or go nearly as low. But it had 2x as much "kick" to it.

My main speakers are Rocket RS-550 and bigfoot center channel. I've had them since the beginning.

I've swapped a/v receivers multiple times over. So Audyssey has nothing to do with it. In fact, it's helped to tame a shrill upper midrange (?) issue that was hurting my ears.

I will try REW again. I wasn't able to get it working the last time I tried. Maybe my new sound card will help with that.
 

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Discussion Starter #9 (Edited)
Setting up REW really kicks my brain. But this time, the sound card was easy to calibrate. It was getting everything else sorted that took a few hours. And with REW, you really-really-really need to pay attention to EVERY word. There is no menutia (sp?). This is pretty tough for a guy like myself with an attention span shorter than that of a squirrel on crack.

One of the problems is it would not read my radio shack SPL meter at the "80" setting on the meter. I had to bring the meter down to "70" before REW would even recognize it. That took forever to figure out!

Then I battled with REW telling me that the test wasn't loud enough to graph. Eventually I just took a shortcut and set the SPL level in REW about 20db above what my meter said it was. That finally spit out this graph:



Look like I have some issues around 75hz. That is midbass territory, right?

EDIT: NEVERMIND, that is only my main speakers. My subwoofer was never active at all.

LET ME TRY AGAIN. arggh.
 

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Discussion Starter #10
I moved my speakers from 1.75' from the wall, closer, to about 6" from the wall. And it looked terrible. All I wanted was to "boost" the bass a bit.

So then I moved my speakers further from the wall than ever before. 2.5' away from the wall. And now the graph looks MUCH better. I'm amazed, and I don't know why. :blink:

Again, this is only my mains. NOT my subwoofer.

 

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No, but you can say buttkicker.

So do you have any slam back after moving the mains?

It looks like your mains are set to large, as they obviously don't drop off at any "normal" crossover point that would be used with a sub. Or did you switch them just for the test?
 

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CZ Eddie,

Use the standard graph axis used here at HTS when you post a graph.

Vertical axis = 45dB-105dB
Horizontal axis = 15Hz-200Hz
Mode = LOGarithmic (and not LINear, as you are using).
Use a target of 75dB

When testing subwoofers, turn off the mains and set the receiver to stereo mode with the crossover engaged.

brucek
 

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Discussion Starter #14
I found my midbass slam, but lost it after introducing the receiver back into the equation.

Started out, my subwoofer looking a little worse than this.


Then after hooking up and playing around with my eD EQ.2, I got it to look like this. At this point, some of my missing midbass had returned. I was definately HAPPY!!!!!


Then after routing the signal back through the reciever instead of hooking my sound card directly to the sub amp, and then after setting up Audyssey again, I got this. And I'm no longer happy.


Hoping it was just Audyssey that was messing up, I turned it off and set the receiver to "No EQ". And this is what I'm getting.



So the weird thing is that Audyssey set's my center crossover at 60hz and my mains at 150hz and my surrounds at 120hz and my sub at 80hz. So for the last graph I posted, after turning off Audyssey I also set the mains to 60hz.

I'll keep playing around with it.
I'm supposed to be driving over to pick up a DSP1124 right now.
 

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Discussion Starter #15
So do you have any slam back after moving the mains?

It looks like your mains are set to large, as they obviously don't drop off at any "normal" crossover point that would be used with a sub. Or did you switch them just for the test?

No, the mains had nothing, or little to do with the slam I'm after. :)

I bypassed Audyssey for my earlier testing.
 

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Discussion Starter #16
This is with Audyssey back on and set the way it originally was, with main crossovers at 150hz and center at 60hz.
But I played around with the eQ.2 again.

I don't understand how it can look so terrible one minute and then half an hour later when you go back to the same basic settings, it looks a ton better.



Thats it, I'm done for the night.
 

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Eddie, if you are trying to measure your sub woofer only you will have to go in and change a couple settings on the Onkyo to route the signal to the sub. It took me a couple hours of fiddling around and googling to get it figured out.

You have to set your input that you are using to 2 channel on the reciever. Then go into the speaker settings and set the mains to full range. Set the double bass setting to on and then disconnect your mains. It's a pain, but that's the only way you can isolate the sub and get it to output a signal that you can measure through the reciever. It's an Onkyo quirk.

When you are setting your RS SPL meter, use the pink noise generator on the reciever to establish a 75db reading on your SPL meter at the main listening position. Then go to the REW panel and calibrate the meter. Take your readings and post em back up in the standard format that brucek mentioned. There is a button in the upper right hand corner of the main REW window labeled graph limits that will set the graph the way you need it.

Hope that helps.
 

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Discussion Starter #18
Eddie, if you are trying to measure your sub woofer only you will have to go in and change a couple settings on the Onkyo to route the signal to the sub.
Thanks for the heads up.
I'm good though. Am running monoblocks to each of my speakers. So I've just been turning the amps off when I wanted to hear the sub by itself. :)


When you are setting your RS SPL meter, use the pink noise generator on the reciever to establish a 75db reading on your SPL meter at the main listening position. Then go to the REW panel and calibrate the meter.
That was step #3 I think. I did it. But I still had level problems which is why I gave up and just fibbed the SPL in REW.

Take your readings and post em back up in the standard format that brucek mentioned. There is a button in the upper right hand corner of the main REW window labeled graph limits that will set the graph the way you need it.
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Did that. But I have no idea what he's talking about when he said:

Mode = LOGarithmic (and not LINear, as you are using)

I picked up a DSP1124 tonight for $55 locally. I'm going to try it out soon.
 

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I agree with Sonnie. Also, make sure to set your spl meter in REW so that you are measuring at 75db. I see one at about this level and another at 105db. That high and you can start to put your subwoofer into compression which could skew your results. Some of your graphs also look suspiciously good ;)
 
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