My first attempt.....how does this graph look?

[dvboy]

Played with REW for my first time today,took me a while to figure things out,can't honestly say I really know what the I am doingAnyway my sub is a duel sealed unit with 10" drivers independent from each other.The room is large,open on one side,so it is a very big area to fill,not sure how that effects things,but here it is.......



Dave

[Wayne A. Pflughaupt]

Pretty impressive; it's not often you see 10" subs that will dig down all the way to 20 Hz. Really smooth response, I doubt you'll even need an equalizer

Your level seems a tad low, but that's about it. Did you calibrate for 75 dB?

Regards,
Wayne

[dvboy]

Hi Wayne
I am not sure what level I calibrated it for,I just set it at a fairly high level and let it do its thing.It was loud enough to shake the windows a bit,so maybe my meter was not set up properly?

[thebuffman]

wow dvboy that is an awesome response from your sub! what are the dimensions of your room and where is your sub sitting?

[thebuffman]

dvboy wrote:

Hi Wayne
I am not sure what level I calibrated it for,I just set it at a fairly high level and let it do its thing.It was loud enough to shake the windows a bit,so maybe my meter was not set up properly?

you calibrate it best using an spl meter. turn on the "subwoofer" pink noise generator through the REW software by selecting the "cablibrate" button, and modify the receiver's volume until the spl meter reads approx 75db. Once REW is calibrated at 75db through this method, you can then check your response and graph it in confidence that your level is 75db.

[dvboy]

thebuffman wrote:

you calibrate it best using an spl meter. turn on the "subwoofer" pink noise generator through the REW software by selecting the "cablibrate" button, and modify the receiver's volume until the spl meter reads approx 75db. Once REW is calibrated at 75db through this method, you can then check your response and graph it in confidence that your level is 75db.

Yea.....that makes sense.When I calibrated my meter,I did it wrong.I will have another go at it today.The room is about 40' x 18'.

[thebuffman]

that's a nice rectangular room...good for HT. i like that rack you have over on the right side! i would love to have something like that to secure my rack mountable apc unit and feed back destroyer.

btw i feel for your seahawks man....but not as bad as i feel for my lions.

[dvboy]

Well I think I got the meter calibrated properly.Looks like my sub is doing very well in its frequency range(80hz and below) anything above 80hz and things get a little out of wack.Here is sub only...


Here is the sub with the two mains...


And strangely enough the flattest one is in pro-logic with the center channel...




Anyway,my new drivers (dayton 10" HF)seem to be doing there thing

[thebuffman]

man bro that is drop dead gorgeous! you have the perfect room not requiring any kind of equalization.

unless you wanted to add a hard knee curve, you are all set and right out of the box. check out my completed hard knee curve graph if you get a chance. it adds a fantastic listening experience when it comes to movies!

[Tommy D]

WOW! That response is incredibly low. Tell us about your sub. Dimensions and amp. Tommy D

[thebuffman]

Tommy D wrote:

WOW! That response is incredibly low. Tell us about your sub. Dimensions and amp. Tommy D

i'm running dual outlaw lfm-1 plus' and the behringer fbd 1124p to equalize them. ......

oh! u meant dvboy

[dvboy]

Hey Tommy,I made the cabinet about 20 years ago.At the time when I made it there was no where near as much information as there is now,so I decided on a duel 10" sealed unit thinking sealed is much less technical.The wall thickness is 1 1/2" all the way around and each side is independent from the other at 1.2 cf.Inside,the middle wall sharing the 2 sides is V shaped to give the walls a different angle,read somewhere that its better to not have parallel walls,not sure if it really had any effect.Overall it weighs about 200lbs.If you look near the bottom you can see a wood plate,that used to be where I played around with a couple of ports,but found the bass to be too muddy,so I sealed it back up again.To be fair 1.2 cf is not enough to properly port,so it was more of an experiment than anything.Recently I upgraded to a couple of Dayton 10" HF drivers in there,was told the ideal box size was 1 cf,but with a sealed unit sizing is not as critical,and my larger(1.2 cf) cabinet should go a little deeper.I also stuffed a little sound proof insulation in there for good measure.Driving them is an beefy Adcom GFA-555II amp that is rated at 325 wpc @ 4ohms.These drivers are rated to handle 350 wpc,so it seemed like a good match.

[Tommy D]

dvboy, is that thing really coming in at about 18hz?

[Wayne A. Pflughaupt]

dvboy wrote:

Driving them is an beefy Adcom GFA-555II amp that is rated at 325 wpc @ 4ohms.

Luv those Adcom amps! That sub/rack combo is pretty nifty.

Regards,
Wayne

[dvboy]

Tommy D wrote:

dvboy, is that thing really coming in at about 18hz?

Tommy,I am a rookie at this,so it is possible my SLP meter is not calibrated properly or what ever else could give a false reading.All I can say is these are the graphs it is spitting out.I am thinking about picking up a Galaxy CM-140,that might add more certainty?

[dan77]

I bought the Galaxy and I couldn't put it down for days. All the charts I got were so much fun. But I had to use the 'crawl technique' to find the best spot. Now, with the help of REW, I was able to find the best locations. One is right behind the couch and the other is in front of the coffee table

[dvboy]

Tommy D wrote:

dvboy, is that thing really coming in at about 18hz?

OK....I have a follow up.I purchased a Galaxy 140,the calibration file was loaded,sound card set up,so I think these graphs are as factual as I can get.I have the crossover set at 80hz on my receiver.They don't look as flat,but I am looking for some feedback as to how things look......

Sub only


Sub&Mains

[al bundy]

Change your graph settings to vertical = 45db-105dB. Looks like you have a pretty good hump in the 35-55Hz range, probably from the corner placement. You could get rid of that with some EQ and maybe boost a little of the low end if your subs can take it being 10's? You can also fix the 80Hz dip with some phase adjustment or distance adjustment. All in all, pretty impressive for a couple of 10's.

When you do sub only, do you physically disconnect the mains?

[dvboy]

Ooops,not sure how my vertical got messed up,here it is again.

Sub Only


Sub&Mains


The graph with the sub only does have the speakers physically dis-connected at the speaker posts.I do have a Reckhorn B1,which has a 1 band EQ,would it be better to give a little boost in the 70hz area?

[brucek]

would it be better to give a little boost in the 70hz area?

You need to remove the peak between 30Hz and 65Hz.......

brucek

[dvboy]

brucek wrote:

You need to remove the peak between 30Hz and 65Hz.......

brucek

OK,as suggested above,would moving the sub to a different location help?My only option would be to move it right next to the TV and switch its position with the right speaker.In theory could this help?It looks like an easy move,but the sub and rack weigh almost 300lbs,so it would be nice to know if its worth a try before hand

[brucek]

would moving the sub to a different location help?

Yes, it could help or make it worse. It will be different though.

brucek

[dvboy]

LOLI have some time today,I'll give it a shot

[dvboy]

I moved the sub,here is a graph with 3 lines.The green line represents its new location.The blue line is the new position with a boost at 20hz,and the upper off blue color represents the old location near the corner.My guess is that the boosted blue line is the best,but how acceptable is it??



Here is a solo graph of the blue line.....

[dvboy]

And here is another with the boost at 20hz turned 3/4 the way to the max on the Reckhorn B1.It looks good to me,but I am not sure how abusive that can be to the subs?