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Raven,

Is your room perhaps in a basement? Does it have concrete floors? What is the wall construction? Concrete or brick as well? You have a huge amount of free low end going it appears. Looks like 15 or 20db at 10hz.
 

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Discussion Starter #145
Raven,

Is your room perhaps in a basement? Does it have concrete floors? What is the wall construction? Concrete or brick as well? You have a huge amount of free low end going it appears. Looks like 15 or 20db at 10hz.
No, second floor, open to a dining room, big cutout in wall (breakfast bar) open to kitchen. Long hall to the end of the house, and stairs going down into the basement.

The sub is 6' from the corner firing into the corner though.

As I said, now that I have my sound card and REW issues sorted out, I'll recalibrate and re-measure to prove or disprove my measurements. I'm pretty sure they will come out pretty close to the same though. The only things that could really be throwing this measurement off, are the calibration files. I'm using the generic Behringer cal file in the downloads section. I guess my mic could easily be off...but then my measurements from last year with the old sub don't show gain below 20Hz...in fact, it drops like a rock below 30Hz (as was expected with the old JL Audio drivers).

If you have any suggestions on how I can verify these measurements, without running out and buying better measurement gear, I'm all for it.

I do have a Radio shack digital meter. I could re-measure the sub and seating position, but I thought the Rat Shack meters were even less accurate then the Behr mics.
 

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Raven,

Is your room perhaps in a basement? Does it have concrete floors? What is the wall construction? Concrete or brick as well? You have a huge amount of free low end going it appears. Looks like 15 or 20db at 10hz.
Maybe we are looking at two different things but the difference between the near-field and seating psn is only showing about 8-9dB @ 10Hz.

Kevin Haskins
Exodus Audio
 

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Discussion Starter #147
OK, re-measurements, plus a full spectrum measurement. I wasn't sure what setting to use on the Onkyo while doing the full spectrum measurement, so I just left it as All Channel Stereo. Please keep in mind, the sub was turned 90 degrees clockwise from last weeks measurement. I figured this would help remove reflections off the L channel speaker as an issue, and I still had it turned this way since making the excursion video last week. So you will see slightly different pits of despair.

This first measurement is Last Weeks plus this weeks with the mic on axis, 2" from where the cone meets the dust cap. Pink is last weeks, blue is this weeks. Besides a slight level difference, it looks pretty close to me.




Here is from seating position. Last weeks is in pink (driver facing forward last week), green from this week (driver facing to the right), and gold is with the mains connected and receiver set to All Channel Stereo.




And this final one, is full spectrum, 5Hz to 20kHz with 1/6th smoothing, receiver set to All Channel Stereo, as measured from seating position. It looks like the sub is running hotter then the rest of the system, and I have a hell of a lot of drop off after 10k. No wonder my system doesn't seem so dynamic.


 

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Raven, I am sorry. I take it back. I just watched it again, this time full screen, and WOW! That is an AWESOME vid, and, that thing really does get moving. I'm glad to eat my own words, I couldn't get it to go full screen the 1st time and I was so excited I didn't think to click "open in youtube". What a difference.

So can you please describe to me the 3Hz and 8Hz tones that I believe are in that track? It sure looks neat, makes me consider 4 sealed in the van if the sub 15Hz material is worth it... but I doubt it is? I mean, I bet you feel tactile 8Hz tones but thats just not worth the trade off to me for a 15Hz vented.
 

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Discussion Starter #149
The problem with single digit tones (besides that you can't really hear them) is that the EP2500 just doesn't have the grunt to push the driver at those frequencies. If I remember from the posted real word measurements, the EP2500 only puts out 600+ watts at 20Hz...and I assume drops below that.

As it is, when I hit single digit tones, you don't feel it in your chair (unfortunately) but you do sense it. My friends during the Star Trek movie night said their eyes watered during the Clubbed to Death video when it got really down low. I'm very sensitive to pressure and I feel it like the sensation when you're driving down a steep hill or going down a fast elevator in a tall building. You feel a slight pressure difference, but that's it.

15hz and up is a different story.

The Fiance and I have been watching Merlin (BBC TV series), and the intro has some 20hz and below ultra-deep bass that just shakes the snot out of the room (I wonder if they even know they went that deep, it seems excessive honestly). Any Sci-Fi show that has the ambient noise of a starship engine really seems to fill the room and gives you the sense you are on the ship with them...though I feel that is probably upper bass because it almost sounds like I forgot the pink noise generator on.

As you probably saw in my other thread, I'm seriously considering a second 21" sealed. I'm really enjoying what I have, and I'd just like that little bit more. Though I have a feeling a better amp that can drive those single digit frequencies at 1500watts might be an equal or better improvement for the sub-sonics...a second sub would really just be for fill and more effortless bass.
 

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After seeing some talk on AVS under the dts10 thread, Ive been reconsidering the EP2500 EP4000 for my 21's.... I don't know if I have the $$$ for Face though, especially the 2 Kevin has the deals on (had? idk, haven't been keeping up)
 

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After seeing some talk on AVS under the dts10 thread, Ive been reconsidering the EP2500 EP4000 for my 21's.... I don't know if I have the $$$ for Face though, especially the 2 Kevin has the deals on (had? idk, haven't been keeping up)
Why not try for a used QSC PLX2502? They can be had on ebay for about 5 to 600 and they have been great for me. I have (2) 2502's a 3002 and a 3402 and they have served me very well. Your not going to find too many people who have a bad thing to say about QSC amps.
 

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After seeing some talk on AVS under the dts10 thread, Ive been reconsidering the EP2500 EP4000 for my 21's.... I don't know if I have the $$$ for Face though, especially the 2 Kevin has the deals on (had? idk, haven't been keeping up)
You might try using a pair of those cheap Behringers per driver. The voice coils are a high-ish 2-Ohm but if you look at the impedance curve in-box, they stay above 3-Ohm most of the time. I bet one of the EP-2500s per coil would give you stupid amounts of power. It should be enough to toast the driver or at least pound it to death.

Kevin Haskins
Exodus Audio
 

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Discussion Starter #153
You might try using a pair of those cheap Behringers per driver. The voice coils are a high-ish 2-Ohm but if you look at the impedance curve in-box, they stay above 3-Ohm most of the time. I bet one of the EP-2500s per coil would give you stupid amounts of power. It should be enough to toast the driver or at least pound it to death.

Kevin Haskins
Exodus Audio
Are you condoning arc welding with your voice coils? :rofl:

Seriously though, am I wrong in wanting an amp that will provide 1500 watts of power across the M-21s usable range? Wouldn't I notice an improvement in low end output if the driver was actually seeing more then the 600 watts that the EP2500 eeks out below 20Hz?
 

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One last thing on the QSC amps. In my large room my M-18 will soak up more power than the 2502 can deliver but the 3402 pounds away with no problem at all. When Kevin says the Mael-X line can take a bunch of power he isn't kidding. The more power the better in a sealed alignment for the M-X series.
 

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Why not try for a used QSC PLX2502? They can be had on ebay for about 5 to 600 and they have been great for me. I have (2) 2502's a 3002 and a 3402 and they have served me very well. Your not going to find too many people who have a bad thing to say about QSC amps.
i may do just that, but then I went from $260 a piece.... $520 for 2 to $550 a piece, $1100!

Then maybe I should get 1/2 off on a abeastly Face from kevin

MEH! $$$$$$$$$$$$$
 

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You might try using a pair of those cheap Behringers per driver. The voice coils are a high-ish 2-Ohm but if you look at the impedance curve in-box, they stay above 3-Ohm most of the time. I bet one of the EP-2500s per coil would give you stupid amounts of power. It should be enough to toast the driver or at least pound it to death.

Kevin Haskins
Exodus Audio
Thats funny, Kevin, cuz that's actually the other thing I have been thinking... once again, I double $$$ on amps, and then my new house is OLD and has fuses, so I am pretty sure I gotta pay $$$$ to redo my electrical... not wanting to do that... but then maybe I can get a dedicated for 4 EP2500s and everything else I'm gonna have to buy soon

1 2500 per coil.... and you say " should be enough to toast the driver or at least pound it to death "? Are you kidding me?
 

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Discussion Starter #157
Ryan, just for you, I pushed the system a little bit last night with that song you've been going nuts about (different then the song I posted in this thread, but put together by the same guy).

I got the sub to (how did Kevin say it?) "make noise" at 3Hz, and though I didn't bottom it out, I'm positive I'm on the ragged edge of the drivers physical capabilities...at 3Hz at least. LOL

I'll post the video tomorrow...I'm out of town today and I don't have the little Point and Shoot camera with me.

Also, I've posted over at ROE, but my post hasn't shown up yet...I don't think I've been approved by the admins or something.

As I have more time over the weekend, I'll also do some sweeps in a more reasonable audio range and see what the excursion looks like. 3Hz is obviously not something this woofer likes, and I had to turn it down a bit for fear of damaging it. I think if I do some sweeps and music in the 5 to 50 range, it should make for pretty conversion of electrical energy to mechanical energy.
 

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Ryan, just for you, I pushed the system a little bit last night with that song you've been going nuts about (different then the song I posted in this thread, but put together by the same guy).

I got the sub to (how did Kevin say it?) "make noise" at 3Hz, and though I didn't bottom it out, I'm positive I'm on the ragged edge of the drivers physical capabilities...at 3Hz at least. LOL

I'll post the video tomorrow...I'm out of town today and I don't have the little Point and Shoot camera with me.

Also, I've posted over at ROE, but my post hasn't shown up yet...I don't think I've been approved by the admins or something.

As I have more time over the weekend, I'll also do some sweeps in a more reasonable audio range and see what the excursion looks like. 3Hz is obviously not something this woofer likes, and I had to turn it down a bit for fear of damaging it. I think if I do some sweeps and music in the 5 to 50 range, it should make for pretty conversion of electrical energy to mechanical energy.
SICK SICK SICK! 3Hz is retarded crazy! I am excited... glad youre posting on ROE too, they need to see what REAL drivers and alignments are ;)
 

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Discussion Starter #160 (Edited)
SICK SICK SICK! 3Hz is retarded crazy! I am excited... glad youre posting on ROE too, they need to see what REAL drivers and alignments are ;)
I'm sure they are familiar with great drivers and well built boxes over there....I've never frequented that forum, but I was under the impression that they are just one note SPL guys...not really my kind of crowd. But I'm happy to show off the M-21, and hopefully send some business Kevin's way.
 
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