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post #271 of 802 Old 04-27-2010, 12:10 PM - Thread Starter
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Originally Posted by Ricci View Post



Ok. Just eyeballing your graphs I'd guess at trying a 39hz cut of about 8db with a Q of 4 or 5 and see what that does. Adjust the Q and cut depth until it looks about right. Try to get the 35-50hz range about in line with the 80hz area. As for a low end boost try a 26 or 27hz, 12db shelf filter with about 5 or 6db of boost to start. Don't go too crazy with the boost level. You may need to add another fairly narrow band of EQ cut around the shelf hinge frequency to even that area back out afterwards. Next set of graphs extend the FR down to 8-10hz.

Is it possible to do this in REW? I.e., adding a shelf filter?

 

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J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #272 of 802 Old 04-27-2010, 12:13 PM
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Originally Posted by pbc View Post

Are there low cost options available that allow one to calibrate at higher levels? E.g., True RTA (think that's what it was called)?

Well, I suppose someone should e-mail or talk to the author. Why it's limited to 99.9dB is beyond me. It should be a pretty simple software change to let you use calibration function at higher SPLs.
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post #273 of 802 Old 04-27-2010, 12:40 PM
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Quote:
Originally Posted by pbc View Post

Is it possible to do this in REW? I.e., adding a shelf filter?

Don't know. I don't even use REW's calculate filter functions.

I thought that you had a DCX? That's what you would use. Adjust the EQ then measure, tweak the EQ further,, measure. Wash, rinse, repeat.
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post #274 of 802 Old 04-27-2010, 12:43 PM
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Quote:
Originally Posted by pbc View Post

Are there low cost options available that allow one to calibrate at higher levels? E.g., True RTA (think that's what it was called)?


Why do you want to calibrate at higher levels?

You can calibrate at 90dBs and you should have the same response at 110dB.

Are you trying to get max output comparisons?

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post #275 of 802 Old 04-27-2010, 12:48 PM
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Quote:
Originally Posted by pbc View Post

I assume you don't mean the PEQ that is available on the amp (which I wasn't using) but that there is further EQ to boost the low end?

Does anyone know what, if any, high pass or EQ is already built into the Ultra's amp by any chance?

Correct. Sir Edward has told me that there is no HP filtering in sealed mode, but that refers to an added HP for driver protection from over excursion and doesn't mean to say that there is no protection in the amp to prevent DC.

Looking at Ilk's and AVTalk's measurements, it's clear that there is no added HP down to 10Hz, so one can assume it's in the single digits. A close mic to 2Hz will show where and what order the amp rolls off, but that will also be confused with the input signal if that info isn't known as well.

Here's a comparo of Raven vs PBC vs WinISD after stretching the WinISD graph to scale. As I've said before, the AVs roll off slightly at around 200Hz and then climb back to flat, so the model w?LP and the PBC w/LP will differ accordingly. The Raven is shown with no LP, so the model will be in between the Raven and PBC, which it is.



Have you checked for leaks, rattles, buzzing wires, loose driver parts, etc?

C'mon, man, fill your boots! Get the damned EQ and let's fire it up!

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post #276 of 802 Old 04-27-2010, 01:14 PM
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I just clued into this design being very similar to Bosso's Ravens?

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post #277 of 802 Old 04-27-2010, 02:40 PM - Thread Starter
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Originally Posted by penngray View Post

I just clued into this design being very similar to Bosso's Ravens?

Only from the standpoint of them both being dual opposed subs with AV15H's (original design had Tumults I believe) and a similar sized power amp. But similarities end there!

 

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post #278 of 802 Old 04-27-2010, 04:37 PM - Thread Starter
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Quote:
Originally Posted by Ricci View Post

Don't know. I don't even use REW's calculate filter functions.

I thought that you had a DCX? That's what you would use. Adjust the EQ then measure, tweak the EQ further,, measure. Wash, rinse, repeat.

DCX is on order, hope to have it by end of week, but heading to Miami next week and need to prep for the meeting so we'll see how much time I have to play.

 

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post #279 of 802 Old 04-27-2010, 04:44 PM - Thread Starter
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New fan was waiting for me when I got home (wow, ordered it Sunday aft!). Just installed it, took longer to remove the darn 70lb beast of an amp than it did to swap out the fan (had to cut out the existing one).

Aaahhh, MUCH more quiet now. Still audible (which annoys me I'll admit!) but way more palatable then the stock one which sounded like a hair dryer on low. Seems to be ample airflow as well coming out the front (maybe one day I'll try to decrease the fan speed with a resistor).

Oh for anyone interested I ended up ordering this one:

http://search.digikey.com/scripts/Dk...77418246359866

Digikey Partnumber P9751-ND
NMB Technologies Corporation Part Number FBA12G24L1A

 

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post #280 of 802 Old 04-27-2010, 05:02 PM - Thread Starter
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BTW, is there a "dummies" guide to setting LT's (i.e., using shelf filters) and using the DCX to EQ in general? Seems relatively intimidating compared to the SMS-1 I was used to!

 

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post #281 of 802 Old 04-27-2010, 09:27 PM
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re:question about filters.

this may be a little confusing because i am not as good as bosso at graphic overlays.

ricci's filters are about what i would "eyeball" too, so i put them in the dcx software and created the response. then i rescaled and overlayed the dcx response on the actual in-room response. so here we go...

1. i used the the light blue line in room response

2. the red line that "points down" is the ricci suggested filter response. it is comprised of:
a) gain: 5.5db, frequency: 25hz, slope: 12db/oct, type: low-shelving
b) gain: -8.0db, frequency: 39hz, q: 5, type: parametric

3. since the idea is to create a "conjugate" with filters (i.e. an exact inverse match to the frequency response), i flipped the suggested filter upside down. that is the red line that points up. if the filter is perfect, it should trace exactly over the light blue line. it can be seen that it is pretty close. the light blue peak is still a little tighter than the red line so a higher q filter should be used. on the bottom end, the red line overshoots the blue line by a couple db, which is "good enough".



now, can we do better? maybe.

1. again, using the light blue line, let's see if we can create a better conjugate.

2. the red line that "points down" is the ltd suggested filter response. it is comprised of:
a) gain: 8db, frequency: 25hz, slope: 12db/oct, type: low-shelving
b) gain: -10.0db, frequency: 39hz, q: 7.1, type: parametric

3. the conjugate appears to trace the light blue line a little better.



you will end up with a little dip around 55hz. you could bring that up with another filter, but at some point adding more filters makes the sound worse rather than better, so you may be hitting that point with just two filters.
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post #282 of 802 Old 04-27-2010, 09:36 PM
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"BTW, is there a "dummies" guide to setting LT's (i.e., using shelf filters) and using the DCX to EQ in general? Seems relatively intimidating compared to the SMS-1 I was used to!"

i'm not aware of any guide, but don't be intimidated, after a bit it will be very intuitive. you don't have to understand the theory in order to be able to use filters. download the free dcx software, then just start playing with the filters. you will be able to see (on the graph in the software) how things such as changing filter types, slopes, q, etc. all affect frequency response.

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post #283 of 802 Old 04-28-2010, 12:45 AM
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This is for the DEQ, not sure if it will help.

http://home.comcast.net/~thomasw-2/S...geDEQ2496.html

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post #284 of 802 Old 04-28-2010, 04:52 AM - Thread Starter
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It does look like REW allows one to insert shelfs on top of PEQs. Here is the graph with a PEW at 39.4hz, -10db gain and a Q of 5 and a shelf filter at 30 with a boost of 6.2...



There is a dip around 85db, not sure if I should bother trying to boost that at all, mind you, I guess if it's not a null it might work.

Interesting look if I smooth it to 1 octave for "fun" ...


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post #285 of 802 Old 04-28-2010, 04:53 AM - Thread Starter
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Quote:
Originally Posted by kingpin111 View Post

This is for the DEQ, not sure if it will help.

http://home.comcast.net/~thomasw-2/S...geDEQ2496.html

Thanks, will take a look.

 

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Quote:

J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #286 of 802 Old 04-28-2010, 05:25 AM
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Originally Posted by pbc View Post

Only from the standpoint of them both being dual opposed subs with AV15H's (original design had Tumults I believe) and a similar sized power amp. But similarities end there!

Similar volume too, no?

btw, too bad you will be away next week. I would have loved to hear it.

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post #287 of 802 Old 04-28-2010, 05:49 AM - Thread Starter
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My volume is about 90 to 95L before stuffing, Bosso mentioned above his is 90L, not sure if he stuffs or not (that sounds somewhat humorous btw). So they could be.

But IIRC, his AV15H's are wired to deliver 2ohms to the amp vs. 4ohm for mine (not sure why, but JJ said to go with the 4ohm instead of 2ohm ... maybe to protect the driver?).

Obviously his is more of a dual opposed cylinder design (and a gorgeous one at that! ). He also employed some sort of fan/cooling system on his Ravens which somehow employs an external fan to cool the interior while keeping it a "sealed" design. Plus I think he may have inserted the Bassis board into the actual Raven vs an external one (not sure on that one). I also recall some sort of LED display on his design, don't recall what that was for (can't be DSP I would think given he uses(d) the Marathon 5050 as an external amp?). In other words, seems the design is a tad more advanced design!!

Here is his website btw ...

http://web.mac.com/bossobass.com/iWeb/Site/Welcome.html

I drool everytime I see those subs.

Here's another dual AV15H design that is stunningly finished (wish I had that kind of craftmanship!) that employs a 1000w Digimoda Ice plate amp (starting to wish I went with a plate amp after hearing even that low drone of the pro amp last night during soft passages, though I'd be giving up some 600 to 800 watts per box) ...

http://www.avsforum.com/avs-vb/showthread.php?t=1187720

Wait, I drool evertime I see that sub too. WTF!? Am I coming out of the sub closet here!?


 

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Quote:

J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #288 of 802 Old 04-28-2010, 05:51 AM - Thread Starter
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Oh, let me know next time you're in town. Hopefully by then I'll have the fronts on and the DCX setup. Odd that I'm heading to Miami and you're heading to Toronto on the exact same dates!!

 

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Quote:

J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #289 of 802 Old 04-28-2010, 05:52 AM - Thread Starter
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BTW, does anyone know of a link where it shows how someone glued their fabric on to the mdf for grills? I can't wrap my head around how to do this (i.e., given I'm using glue I can't exactly "clamp" the fabric down on the wood I don't think and need the fabric to fit tightly obviously).

 

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post #290 of 802 Old 04-28-2010, 05:57 AM
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From the grills I have seen, some people will route out a small valley on the inside of the grill, likely applied glue of some kind in the valley and pressed the fabric down into the valley with a putty knife until it dried... JJ had a nice clean finished look, but I haven't gotten my boxes yet, so I can't post a pic...

Im sure there will be other methods described, plus there are threads on it as well... search titles for grill or grills.
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post #291 of 802 Old 04-28-2010, 06:09 AM - Thread Starter
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Penn mentioned some sort of 3M spray glue or something in Reece's thread where he used hot glue.

Penn - is this what you use?

http://solutions.3m.com/wps/portal/3...er-77/Super77/

 

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post #292 of 802 Old 04-28-2010, 06:11 AM
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3M 77 works very, very well with fabric and a MDF Frame. Yes, its what I used.

If you want maybe some custom grills to fit just over the 15" woofers then maybe you chould contact CSS

here is an example of a 10" grill.
http://www.creativesound.ca/details.php?model=MG-10

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post #293 of 802 Old 04-28-2010, 07:25 AM
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The 3m spray adhesive works well. However, you had better get it right the first time as it doesn't really give you a second chance. Another option that works well is to run all four sides of the grill frame down the table saw with tht blade set at about 3/16" depth. Then you buy some window screen spline and use that to hold the cloth in the slot you just made. It's a bit morr work than using the glue but the glue method is harder to get right.

Regards,

Dennis
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post #294 of 802 Old 04-28-2010, 07:34 AM
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LTD,

Nice. The graphics work for me.

I also like the fact that you can affect different delays for each sub from a single input.

How about FR, noise, transparency and clipping? Any measurements available? The specs say it rolls off at 10Hz but I don't believe any of the specs in Behringer spec sheets.

IOW, what can a Bassis do that a DCX can't? Stay flat and remain clean and dead quiet? I'd like to know without having to shell out the cash and do the tests myself.

Bosso
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post #295 of 802 Old 04-28-2010, 07:47 AM
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Quote:
Originally Posted by pbc View Post

My volume is about 90 to 95L before stuffing, Bosso mentioned above his is 90L, not sure if he stuffs or not (that sounds somewhat humorous btw). So they could be.

But IIRC, his AV15H's are wired to deliver 2ohms to the amp vs. 4ohm for mine (not sure why, but JJ said to go with the 4ohm instead of 2ohm ... maybe to protect the driver?).

Obviously his is more of a dual opposed cylinder design (and a gorgeous one at that! ). He also employed some sort of fan/cooling system on his Ravens which somehow employs an external fan to cool the interior while keeping it a "sealed" design. Plus I think he may have inserted the Bassis board into the actual Raven vs an external one (not sure on that one). I also recall some sort of LED display on his design, don't recall what that was for (can't be DSP I would think given he uses(d) the Marathon 5050 as an external amp?). In other words, seems the design is a tad more advanced design!!

Here is his website btw ...

http://web.mac.com/bossobass.com/iWeb/Site/Welcome.html

I drool everytime I see those subs.

Here's another dual AV15H design that is stunningly finished (wish I had that kind of craftmanship!) that employs a 1000w Digimoda Ice plate amp (starting to wish I went with a plate amp after hearing even that low drone of the pro amp last night during soft passages, though I'd be giving up some 600 to 800 watts per box) ...

http://www.avsforum.com/avs-vb/showthread.php?t=1187720

Wait, I drool evertime I see that sub too. WTF!? Am I coming out of the sub closet here!?


To clarify; the AV Ravens I've built used the SVC 4 ohm version. Each Raven is 8 ohms nominal and a pair of them in parallel is 4 ohms driven by a single RMX 5050 or Marathon MA 5050.

I haven't inserted a Bassis board into a Raven, but I have designed an on board processor that used to be pictured on my site that was built into the front panel of the Executive version. That was 6 years ago and I've abandoned that route since A/V receivers and outboard EQ have gotten sophisticated enough to offer quality tweaks to a passive sub system.

In any case, the idea was to explore every inch of the chain for optimum performance, which took literally thousands of hours of theory, planning, building, testing, graphing, tweaking, etc.

There is a mountain more to it than plug and play of a box with a driver in it powered by a pro sound amp. Well, that's been my opinion anyway, FWIW.

djarchow's subs are 1st class. I wish he'd post more pics.

Bosso
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post #296 of 802 Old 04-28-2010, 08:06 AM - Thread Starter
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Oh, for some reason I thought I recalled in your thread that you had 2ohm to the amp!

Yeah, wish Dennis had posted more build pics!

 

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J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #297 of 802 Old 04-28-2010, 08:08 AM - Thread Starter
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Quote:
Originally Posted by djarchow View Post

The 3m spray adhesive works well. However, you had better get it right the first time as it doesn't really give you a second chance. Another option that works well is to run all four sides of the grill frame down the table saw with tht blade set at about 3/16" depth. Then you buy some window screen spline and use that to hold the cloth in the slot you just made. It's a bit morr work than using the glue but the glue method is harder to get right.

Regards,

Dennis

True, but then I'd need a table saw!

Might try that with a router and a guide I guess, though not sure I can get a 1/16" bit to mimic the width of a saw blade. Plus I'll have very little wood to work with on the sides (maybe 3/4" thick) for the grills so not sure I want to risk it. We'll see. Will try on some scrap first as usual.

 

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Quote:

J Dunlavy:.. if you stop to think about it, no loudspeaker can sound more accurate than it measures.

 

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post #298 of 802 Old 04-28-2010, 10:49 AM
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Quote:
Originally Posted by bossobass View Post

LTD,

Nice. The graphics work for me.

I also like the fact that you can affect different delays for each sub from a single input.

How about FR, noise, transparency and clipping? Any measurements available? The specs say it rolls off at 10Hz but I don't believe any of the specs in Behringer spec sheets.

IOW, what can a Bassis do that a DCX can't? Stay flat and remain clean and dead quiet? I'd like to know without having to shell out the cash and do the tests myself.

Bosso

I've got the FR measurement from one of my DCX's somewhere...Let me see if I can dig that up. I want to say that it was very flat down till the 5hz range but don't quote me on that...
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post #299 of 802 Old 04-28-2010, 10:52 AM
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Nice graph's LTD. I wasn't too far off on my filter guesses! I'm surprised. All of that time playing with EQ's must've sunk in a little.
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post #300 of 802 Old 04-28-2010, 11:39 AM
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Quote:
Originally Posted by Ricci View Post

I've got the FR measurement from one of my DCX's somewhere...Let me see if I can dig that up. I want to say that it was very flat down till the 5hz range but don't quote me on that...

I was sure that Illka on the HT Shack did a measurement of it, but it was buried in a thread somewhere.

I can check to see if I have one of it with all processing turned off. There is a slight latency through the DCX, IIRC about a msec.

"You take the blue pill - the story ends, you wake up in your bed and believe whatever you want to believe. You take the red pill - you stay in Wonderland and I show you how deep the rabbit-hole goes."
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