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My multi location subwoofer thread inspired by Welti,Devantier,Geddes !!! - Page 2

post #31 of 190
12/28/11 at 7:20am
Thread Starter 
At this point im sure my 600lb behemoths are going to stay where they are. From the illistrations, my first choice would be to put another sub against the rear wall and play around with that location.

Most have said to augment with a small 10" sub. I think i will pick up a moderate 15 and a reasonable plate amp. The Dayton drivers are nice. If i go small and sealed i will probably get no lower than 35hz out of it without EQ.

...but first my OM has to make it off the FedEx truck...

..... I did pick up a nice mic stand with a mic clip at my local Pro Audio store here in town
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post #32 of 190
12/28/11 at 1:20pm
Are you using a laptop, or PC?

The reason I ask, that I bought a long USB extender for mine shortly after I bought it. I have a PC I use in the same room,...but either way, I think an extended cable will give you a lot more flexibility.
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post #33 of 190
12/28/11 at 5:21pm
Thread Starter 
Quote:
Originally Posted by FOH View Post

Are you using a laptop, or PC?

The reason I ask, that I bought a long USB extender for mine shortly after I bought it. I have a PC I use in the same room,...but either way, I think an extended cable will give you a lot more flexibility.

Laptop, i gotta find your link in the other thread

Picked up a 10' belkin for about $3 ....... Looking forward to a nice four day weekend to get some work done....Audio work, that is
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post #34 of 190
12/29/11 at 6:46pm
Thread Starter 


so here is a screen shot of all four co-located subs in the front of the room. Audyssey is on , as well as DEQ.

that would be the center seat head height reclined.... thoughts. once i figure how to save all three head locations, i'll post it.

this OM is a pretty cool device. i just scratched the surface......Its 1/6th oct
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post #35 of 190
12/29/11 at 7:52pm
Thread Starter 


somethings gotta be wrong, thats three locations......1/6th audyssey on/DEQ on....

looks like my idea of building more subs to smooth things out is about done, unless I'm missing something. Maybe being spread across the front, and out in the room flattened them out more than i thought...
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post #36 of 190
12/30/11 at 10:43am
Thread Starter 
So i did a quick check to make sure they were all equal in output level, and now they are.

Would i run a sweep to check the subs capability at the LP ?



so at the LP, i ran the noise track#1 and to my surprise 95db was damn scary. never saw the drivers do a dance like that. tryed to keep testing cycles to about 10 seconds..... dont want to melt anything....

holy crap.... left the volume up on the 3rd track and i think all four drivers fell out LMAO
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post #37 of 190
12/30/11 at 11:13am
Thread Starter 
on the third track long sweep, the distorsion test resulted in this graph, can you explain what it meant. only the 2nd harmonic was used, should i show results up to the 5th, again..why ?

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post #38 of 190
1/2/12 at 3:19pm
Quote:
Originally Posted by A9X-308 View Post

Or half way up the wall, as that would then fail to excite the first floor/ceiling mode.

Good point, that's even better.

Quote:
Originally Posted by kgveteran View Post

so here is a screen shot of all four co-located subs in the front of the room. Audyssey is on , as well as DEQ...Its 1/6th oct

I'd turn off DEQ, as its complex algorithm may make your results very inconsistent and unpredictable.

Also 1/6th oct could obscure significant peaks/dips.
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post #39 of 190
1/2/12 at 4:29pm
Thread Starter 
Quote:
Originally Posted by noah katz View Post

Good point, that's even better.



I'd turn off DEQ, as its complex algorithm may make your results very inconsistent and unpredictable.

Also 1/6th oct could obscure significant peaks/dips.

My last sweep was 1/24th, i dont care where it goes, as long as i can fill that aweful null at the LP Red line is just main sub, blue line is BIC-200 behind LP, look how just one sub filled in so much !!!!

Yup all Audyssey was off...

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post #40 of 190
1/2/12 at 5:24pm
Wow big difference for small effort.
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post #41 of 190
1/2/12 at 5:40pm
Thread Starter 
Quote:
Originally Posted by gpmbc View Post

Wow big difference for small effort.

I know, not sure it could keep up with the mains. Cant wait to settle in on a driver... Any suggestions
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post #42 of 190
1/2/12 at 6:11pm
Quote:
Originally Posted by kgveteran View Post

I know, not sure it could keep up with the mains. Cant wait to settle in on a driver... Any suggestions

When I get around to doing the same thing, I was gonna pair up a spare 250w plate amp I've got on hand with one of the Dayton RSS 10" drivers. Nice bandwidth, low distortion, nice top end and it all fits in a relatively small enclosure. There are other options if you need something even smaller though.

Looks like you got pretty damn good results with the BIC sub you have now.
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post #43 of 190
1/2/12 at 7:26pm
Quote:
Originally Posted by kgveteran View Post


I know, not sure it could keep up with the mains. Cant wait to settle in on a driver... Any suggestions

Not off hand. I'm still waiting to implement a bunch of sealed 15s myself so eager to see how it turns out.
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post #44 of 190
1/2/12 at 8:07pm
Quote:
Originally Posted by kgveteran View Post


I know, not sure it could keep up with the mains. Cant wait to settle in on a driver... Any suggestions

Doesn't necessarily have to keep up 100%. Just use enough spl to smooth things, and stop there. If you are concerned, run distortion sweeps nearfield on the auxiliary sub only...

JSS
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post #45 of 190
1/2/12 at 9:49pm
Quote:
Originally Posted by noah katz View Post

Good point, that's even better.

Good to see someone else thinks so. I've mentioned it before to complete silence. As I have a bunch of 12's I'm going to try some there facing up, port at floor level.
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post #46 of 190
1/3/12 at 5:36am
Thread Starter 
Quote:
Originally Posted by maxmercy View Post

Doesn't necessarily have to keep up 100%. Just use enough spl to smooth things, and stop there. If you are concerned, run distortion sweeps nearfield on the auxiliary sub only...

JSS

Nice, great idea. So, if i can get the AUX sub to augment without to much distress, I'll rerun Audyssey with it in place.... The plot thickens.

At a quick glance the 240watt Dayton plate amp and a 12" Dayton sub driver....
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post #47 of 190
1/3/12 at 6:43am
Quote:
Originally Posted by kgveteran View Post

Nice, great idea. So, if i can get the AUX sub to augment without to much distress, I'll rerun Audyssey with it in place.... The plot thickens.

At a quick glance the 240watt Dayton plate amp and a 12" Dayton sub driver....

Yes, that is the crux of the Geddes approach relative to some of the others. You don't need your "filler" subs to have the same output capacity. They might be 6db down at the same frequencies your "primary" subs are playing.

You can also use DSP to limit the bandwidth of those subs to where you actually need the smoothing. Depending on your room size, you probably won't need them below 25hz so you can put a highpass around that point and it will give a smaller sub more output capacity. A smaller box works in the same way.

A Dayton RSS315HF-4 ($150) in 1.5-1.75cu ft sealed with Dayton SPA250 ($120) would work very well. If you really want to get wild, you could build a 4th order bandpass sub. That driver works well for this purpose in about 1.25cu ft back and .750cu ft front tuned to about 47hz. A BP box reduces distortion and the ability to localize which is handy with rear subs.
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post #48 of 190
1/3/12 at 8:13am
Thread Starter 
Quote:
Originally Posted by coctostan View Post

Yes, that is the crux of the Geddes approach relative to some of the others. You don't need your "filler" subs to have the same output capacity. They might be 6db down at the same frequencies your "primary" subs are playing.

You can also use DSP to limit the bandwidth of those subs to where you actually need the smoothing. Depending on your room size, you probably won't need them below 25hz so you can put a highpass around that point and it will give a smaller sub more output capacity. A smaller box works in the same way.

A Dayton RSS315HF-4 ($150) in 1.5-1.75cu ft sealed with Dayton SPA250 ($120) would work very well. If you really want to get wild, you could build a 4th order bandpass sub. That driver works well for this purpose in about 1.25cu ft back and .750cu ft front tuned to about 47hz. A BP box reduces distortion and the ability to localize which is handy with rear subs.

All good points. My hope is that the AUX sub will excite frequencies between 40hz and the XO point of 80hz. For now, i'm on the fence to build or purchase... Which is odd in a DIY section, Lol.

I have to put my trusty BIC-200 through its paces, to see if it keeps up, along with some new locations. I think i will need a MiniDSP to build a response to what i need out of the AUX sub....

this is the best yet. would you agree that this is plus or minus 6db


Last but not least against the side wall even with the seating position.....
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post #49 of 190
1/5/12 at 11:43am
Thread Starter 
My mic is going back, 60hz peak :0(
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post #50 of 190
1/5/12 at 12:17pm
Quote:
Originally Posted by A9X-308 View Post

Good to see someone else thinks so. I've mentioned it before to complete silence. As I have a bunch of 12's I'm going to try some there facing up, port at floor level.

+1

Absolutely, couldn't agree more. Selective Mode Cancellation, I reference it often, both here and at The Cult.

Small sealed/vented enthusiasts can experiment a great deal until the excitation balance is achieved. However, oftentimes an IB manifold build overlooks this crucial element, and places a manifold at locations that may be quite compromised, as opposed to idealized. OTOH, IB arrays are ideal candidates for addressing both height and width modes, but their structural forces are significant, and must properly be tended to.


kg;
Quote:


For now, i'm on the fence to build or purchase

What are your thoughts?
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post #51 of 190
1/5/12 at 1:00pm
Thread Starter 
Quote:
Originally Posted by FOH View Post

+1

Absolutely, couldn't agree more. Selective Mode Cancellation, I reference it often, both here and at The Cult.

Small sealed/vented enthusiasts can experiment a great deal until the excitation balance is achieved. However, oftentimes an IB manifold build overlooks this crucial element, and places a manifold at locations that may be quite compromised, as opposed to idealized. OTOH, IB arrays are ideal candidates for addressing both height and width modes, but their structural forces are significant, and must properly be tended to.


kg;


What are your thoughts?

I have had this on the back burner for quite some time. Once i got the OM home and ran some sweeps that were conclusive, its a done deal.

My build of choice will be a single Dayton 12" sealed , powered by Dayton's 240watt plate amp. One Mini DSP will provide processing of four individual subs. The real cool part is that the sub will probably operate over one octave ( 40hz -80hz ). That driver and amp should be plenty overkill for this project. Seems like a 1.5-1.75cube ft will get me where i want to be.

Nice part of this, is my reference subs hit 10hz-40hz pretty much flat across the LP. They will stay where they are and carry the lion share of the ULF stuff.
As of now, one BIC-200 does the deal and proved to me that this is a very worth while adventure. The small footprint will be easier to place also.....

KG

PS: this is the graph that sold me, look how the BIC sub filled in the huge hole. With a single parametric filter centered at 40hz and an octave wide, I can lower that response almost flat..... Then let Audyssey do its thing.
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post #52 of 190
1/5/12 at 1:11pm
kgveteran/FOH;
I'm following this thread with interest.
Not wanting to hijack your multi-sub experiment, rather join it - for now, possible I'll make my own thread if I choose to further explore this.

For my IB line array set-up, I've got some nulls in my 1st row that after all my broadbass traps in corners/etc still are there.
Specific seat to seat.
2nd row if very-very good.


Is this the "method" in 101 terms:
-Use a parametric EQ (I have a FBQ2496) as a LPF for only the specific trouble freq
(mine are centered around 30 and 35hz, actually I'd block the frequencies above 35 hz and below 30 hz)
-put a "spare" sub in the seat (for this experiment I'd borrow my 14 year old 12" Atlantic technology Model 352 PBM from the family room set-up)
-using REW/other do a sine wave at the trouble freq
-walk the walls to find where I can hear the sub "best" (with spl to quantify)
-repeat for both trouble seat locations
-hopefully find a single location that will satisy both seats and nulls, or pick best compromise again via sine sweep/testing
-then put the sub @ that spot and measure @ the seats...

it's as "simple" as that??

I'm looking to filling in the nulls w/o gaining un-wanted peaks onto the IB sub's response, kinda have my cake and eat it too...

kgveteran;
your charts, are those 1/12 or 1/3 smoothed?
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post #53 of 190
1/5/12 at 1:34pm
Quote:
Originally Posted by FOH View Post

Absolutely, couldn't agree more. Selective Mode Cancellation, I reference it often, both here and at The Cult.

Yes, but to be balanced, let's not forget that this only works on odd-order modes.
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post #54 of 190
1/5/12 at 2:04pm
Quote:
Originally Posted by kgveteran View Post


I have had this on the back burner for quite some time. Once i got the OM home and ran some sweeps that were conclusive, its a done deal.

My build of choice will be a single Dayton 12" sealed , powered by Dayton's 240watt plate amp. One Mini DSP will provide processing of four individual subs. The real cool part is that the sub will probably operate over one octave ( 40hz -80hz ). That driver and amp should be plenty overkill for this project. Seems like a 1.5-1.75cube ft will get me where i want to be.

Nice part of this, is my reference subs hit 10hz-40hz pretty much flat across the LP. They will stay where they are and carry the lion share of the ULF stuff.
As of now, one BIC-200 does the deal and proved to me that this is a very worth while adventure. The small footprint will be easier to place also.....

KG

PS: this is the graph that sold me, look how the BIC sub filled in the huge hole. With a single parametric filter centered at 40hz and an octave wide, I can lower that response almost flat..... Then let Audyssey do its thing.

That is great. You get that at all seats?

JSS
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post #55 of 190
1/5/12 at 5:06pm
Thread Starter 
Quote:
Originally Posted by noah katz View Post

Yes, but to be balanced, let's not forget that this only works on odd-order modes.

What about even order modes ? Do explain. . . . . . . Don't leave us hanging
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post #56 of 190
1/5/12 at 5:56pm
Thread Starter 
Quote:
Originally Posted by maxmercy View Post

That is great. You get that at all seats?

JSS

When i get my mic back i have to do some more sweeps. The three seating position seem to look the same..almost.
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post #57 of 190
1/5/12 at 6:05pm
Thread Starter 
Quote:
Originally Posted by mtbdudex View Post

kgveteran/FOH;
I'm following this thread with interest.
Not wanting to hijack your multi-sub experiment, rather join it - for now, possible I'll make my own thread if I choose to further explore this.

For my IB line array set-up, I've got some nulls in my 1st row that after all my broadbass traps in corners/etc still are there.
Specific seat to seat.
2nd row if very-very good.


Is this the "method" in 101 terms:
-Use a parametric EQ (I have a FBQ2496) as a LPF for only the specific trouble freq
(mine are centered around 30 and 35hz, actually I'd block the frequencies above 35 hz and below 30 hz)
-put a "spare" sub in the seat (for this experiment I'd borrow my 14 year old 12" Atlantic technology Model 352 PBM from the family room set-up)
-using REW/other do a sine wave at the trouble freq
-walk the walls to find where I can hear the sub "best" (with spl to quantify)
-repeat for both trouble seat locations
-hopefully find a single location that will satisy both seats and nulls, or pick best compromise again via sine sweep/testing
-then put the sub @ that spot and measure @ the seats...

it's as "simple" as that??

I'm looking to filling in the nulls w/o gaining un-wanted peaks onto the IB sub's response, kinda have my cake and eat it too...

kgveteran;
your charts, are those 1/12 or 1/3 smoothed?

I used 1/24. I simply plugged the sub in with an extension cord and a long interconnect and slid it around on its side. I chose that one spot because it filled in the null with a nice peak that can be tamed with a single filter centered at 40hz and about an octave wide....

This all came about when i measured HD and saw a big hump around 55hz. Audyssey had tryed to raise the null and only succeded at causing distortion at that frequency. Audyssey is great, but fine tuning helps. I figure the less Audyssey has to correct the better.

So I have to make some cash to get the parts together for the build. Looks like 400.00 will get me a driver,amp,MiniDSP....

Rest assured we are not done, there HAS to be more to it, but time will tell........
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post #58 of 190
1/5/12 at 7:44pm
Quote:
Originally Posted by kgveteran View Post

What about even order modes ? Do explain. . . . . . . Don't leave us hanging

Unlike the odd-order modes, they're not cancelled from opposite wall placement, nor fail to be excited by midwall placement.

See the paper for more explanation.
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post #59 of 190
1/6/12 at 1:37am
Thread Starter 
Quote:
Originally Posted by noah katz View Post

Unlike the odd-order modes, they're not cancelled from opposite wall placement, nor fail to be excited by midwall placement.

See the paper for more explanation.

Reading that stuff is like decoding Hyrogliphics. If i can measure at my seating positions, and get a response that is workable, as i did, isnt that enough, or is there a super secret response that my magic decoder ring didnt pick up..... I'm nor sure i even spelled Hyrogliphics right, there had to be three different ways from a google search....
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post #60 of 190
1/6/12 at 4:49am
Quote:
Originally Posted by kgveteran View Post


Reading that stuff is like decoding Hyrogliphics. If i can measure at my seating positions, and get a response that is workable, as i did, isnt that enough, or is there a super secret response that my magic decoder ring didnt pick up..... I'm nor sure i even spelled Hyrogliphics right, there had to be three different ways from a google search....

Only way to cancel even number modes is by 1/4 wall placement or even more subs. It adds up quick.

Since no room will match up perfectly with theory, what you did is right. When you are measuring near the same at all seating locations and it can be easily corrected to flat w/o a lot of boost, job is done.

You filled in that low spot nicely....

JSS
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