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post #421 of 448 Old 08-05-2011, 12:17 PM - Thread Starter
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Somehow I missed these questions a month ago...I just saw them when I came to update the CEA2010 data.



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Originally Posted by chrapladm View Post

Ricci could this cabinet design be used for live applications?.

I guess it should certainly be loud enough if you use 2-4, for most applications, but really the cab loading is lower than needed, and it is really big and heavy. You could gain a lot of top end output and efficiency in the meat of the live sound range if you moved the corner up a whole octave higher. You know like the Othorn. Basically the Gjallerhorn would be OK 40-90hz, but some smaller, lighter cabs can compare favorably over that range. It isn't until the octave and a half below that range that it starts to set itself apart from the normal live sound gear. In most live or SR instances that sort of content is pretty much non existent anyway though. Everybody usually filters below 30hz pretty heavily to protect their equipment and cabs and live music doesn't have much below 30hz anyway, so the extra extension is wasted in that application.

Don't get me wrong I am using them for live sound right now but they are stationary, it is only for myself and I run the system.




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Originally Posted by 04FLHRCI View Post

Any estimations how one of these guys would perform in a ~3000 cube HT LPF @80Hz?


Violently. The pair that I have have been pushed in the >10,000cu ft very lossy space they are in a few times, just having fun with them and it is more than plenty for that space. They can shake the entire building and easily pressurize the space with Jurassic Lunch and I only have about 1300w of amplifier going to each one. They aren't even using all of that power. Some people say there is no such thing as overkill, but seriously the Gjallerhorn is simply not needed in any sort of domestic environment. Even one will do reference levels to 16hz in a normal room without breaking a sweat. I guess if you had a screen wall it might make some sense, but most of the time I doubt that you would use much of the available headroom. Most situations would be better served with multiple smaller, more modest subs scattered about the room to smooth the response.

I'd be lieing if I said that I wouldn't like to experience what they would do "opened up" in someone's HT room just once though. Maybe someone will have a GTG I can drag one to.
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post #422 of 448 Old 08-05-2011, 12:32 PM - Thread Starter
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Here are the CEA2010 distortion results to go along with the basic output spl numbers.


Gjallerhorn CEA2010 output. Referenced to 2 meters, rms, outdoor groundplane.

10hz-----90.2db-----Distortion
12.5hz---105.2db----Distortion
16hz-----118.3db----Amplifier
20hz-----122db------Driver noise
25hz-----124.9db----Driver noise
31.5hz---125.8db----Driver noise
40hz-----128.4db----Amplifier
50hz-----127.2db----Amplifier
63hz-----130.2db----Distortion
80hz-----130.9db----Amplifier
100hz----131.1db----Amplifier
125hz----123.6db----Amplifier




















Here is 10hz distortion at just about maximum output. Obviously this is not clean or a passing result. This is way below the cab loading and the distortion is very high, but it shows what the Gjallerhorn can do dynamically down that low before getting the driver into mechanical trouble.

93.2db at 10hz
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post #423 of 448 Old 08-05-2011, 12:57 PM
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wow.

did you run out of amp at 100hz and 125hz? is that why the blue line never touches the red line distortion limit or is it something else?

also, it looks like your getting the hang of running these kinds of measurements. hopefully that is cutting down the time required.

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post #424 of 448 Old 08-05-2011, 01:01 PM
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also, what kind of signal is being used for these tests? is it a standard that you can link to or is it something else?

i'm particularly interested the crest factor. manipulating that seems to be increasing in popularity as a way to hit higher peak outputs and appear to have higher sensitivity.

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post #425 of 448 Old 08-05-2011, 01:10 PM - Thread Starter
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The signal is the standard CEA2010, 6.5cycle duration, Hann shaped, 1/3rd octave bursts. 100 and 125hz are very short duration. Nothing more than a blip. The program usually just records them like that.

I ran out of amp at 16hz, 40, 50, 80, 100 ,125hz. There were driver distress noises that made me leery of extra level at 20,25,31.5hz despite low distortion results. Distortion limited 10 and 12.5hz and 63hz. That is if I remember all of this right.
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post #426 of 448 Old 08-05-2011, 03:24 PM
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if running out of amp all over the place, what is actually being measured? is it distortion caused by the driver/enclosure or by the amplifier as it is running into clipping?

edit: i see you updated the numbers with notes. that makes some sense and suggests that there is even more output potential of the subwoofer.

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post #427 of 448 Old 08-05-2011, 03:33 PM
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Quote:
Originally Posted by Ricci View Post

I'd be lieing if I said that I wouldn't like to experience what they would do "opened up" in someone's HT room just once though. Maybe someone will have a GTG I can drag one to.


*laughs* Just kidding. Well, sort of ... I'd go for it if I didn't already have too much on my plate.

Ricci, your Gjallerhorn is CRAZY STUPID CLEAN through the whole lower bass region. Frickin' insane output out of one. It's too bad it gets so 'meh' above 80hz. I bet if you were to cross a cluster of the Gjaller to some uber midbass array you would have the ultimate bass system for outdoor venues. As long as you never had to move them... ever again, anyway.


Love the work you're doing, Josh.

My Dual 18" LLT subs 120dB down to 10hz

 

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post #428 of 448 Old 08-05-2011, 04:42 PM
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is it a big pain to have the scale be absolute instead of relative like the old ed mullen charts? they seemed pretty easy to read. i REALLY like the additional information about distortion limited vs. amp limited. that adds another important dimension.

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post #429 of 448 Old 08-05-2011, 07:11 PM - Thread Starter
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John with this type of burst testing even a 1" dome tweeter can withstand many kilowatts of input in certain frequency ranges. These same power inputs can cook even an LMS coil easily. It is only the very short duration that allows them. Every sub is going to be amplifier limited at a lot of frequency bands.

I like Ed's old charts. I had already been listing the limiting factor for long term signals on my Excel charts. It does make sense to include it for cea2010 as well.
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post #430 of 448 Old 08-05-2011, 09:37 PM
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i see what you mean.

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post #431 of 448 Old 08-19-2011, 08:02 AM
 
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i want this bass horn!!!!
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post #432 of 448 Old 08-19-2011, 08:25 AM
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Quote:
Originally Posted by Ricci View Post

The signal is the standard CEA2010, 6.5cycle duration, Hann shaped, 1/3rd octave bursts. 100 and 125hz are very short duration. Nothing more than a blip. The program usually just records them like that.

I ran out of amp at 16hz, 40, 50, 80, 100 ,125hz. There were driver distress noises that made me leery of extra level at 20,25,31.5hz despite low distortion results. Distortion limited 10 and 12.5hz and 63hz. That is if I remember all of this right.

Excellent results.

Is there a DIY version of this test, or was that a specific package that you used?

I'd love to be able to use the same methodology on my builds - there is a TON of information presented there.
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post #433 of 448 Old 08-19-2011, 10:20 AM
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wow, i've very glad that this thread got brought up again. It's literally a gold mine, between the entertainment of pages 1-7, and the very, very good science and discussion.
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post #434 of 448 Old 08-19-2011, 01:48 PM
 
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over kill or not... i would put this bad boy in a bedroom lol
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"Is there a DIY version of this test, or was that a specific package that you used?"

a "behind the measurements" would make for a great technical article ricci, if you don't think that would be stepping past the line.

----------

"i would put this bad boy in a bedroom"

something about that statement doesn't sound quite right. :-)

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post #436 of 448 Old 08-20-2011, 06:16 AM - Thread Starter
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Mike,
The program runs under a software package called IgorPro. Powerful and very deep software for audio. It is sort of like a measurement and graphical presentation tool kit. What I mean by that is it is sort of open for the user to set up routines or experiments or setup what you want to do. It is $600 for a license if I remember right. The experiment that runs this was created by Don Keele. It is not available for purchase anywhere still. You would also need some other minimum equipment to run it foremost being an SPL calibrator.





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over kill or not... i would put this bad boy in a bedroom lol
I will give the plans to anyone who wants to build it. All you have to do is pm me your email.

I would like to put 2 in the back of a shortie Astro van and see what would happen on a termlab at 16hz myself. Just for fun of course.
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post #437 of 448 Old 08-20-2011, 01:37 PM
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Quote:
Originally Posted by Ricci View Post


Now this is a real curiosity. When I first put the cabs together and applied power I took some close mic graphs. These all show a 100hz dip that was not apparent in the simulation. I then ran the pair lightly in a pa set-up for a few days. Fast forward...I get one of them outside to test it and lo and behold the 100hz dip is gone and between 90-110hz the response has changed. The 100hz dip is no longer there. I freak out thinking perhaps I had damaged something in this cab, or the driver, or both, which wouldn't have been out of the realm of possibility considering the beating bestowed on it, so i run inside and take a measure on the other cab and it is now missing the 100hz dip too. That one hasn't been used very hard at all. I thought that perhaps I somehow had EQ engaged during the original measurements but there is no way. The drivers were brand new and had never been above about 2v so perhaps they had a major break in and this is responsible but I find that a hard pill to swallow. The cabs are 13ply BB with pocket screws and are PL'd together and built by a professional cabinet shop who's owner owns DTS-10's and is familiar with speakers so I have a hard time believing that a panel came loose and shifted enough to cause the response change either. I am at a loss to explain it really. I have attached a couple of measurements illustrating this as well. The 100hz notch is easily seen in the original measurement. The other one is the current response where there is no longer a 100hz dip. Very odd. Atleast it is a response improvement.







Attachment 214743
Attachment 214742

Just doing some catching up and noticed this post. Since I was reading through, I remembered this post before it:

Quote:
Originally Posted by Ricci View Post


Bentz,
These quick and dirties are with the mic positioned middle of the mouth and coincident with the plane of the side. The cab is rotated tall with the mouth off of the floor and the whole thing is on a furniture dolly rolled outside onto a dock.

It seems likely that your mic was exactly 1/4 wave distance from the floor (33-34") for your close mic graph and otherwise for the measurements that show no null at 100 Hz.

Without the dimensions, I'm just taking a probability stab at this. Maybe you can verify the distance of the mic-to-floor dimension in the 100 Hz null measurement vs the non-100 Hz null measurements?

To verify if this is the case, you could repeat the exercise (measure one with mouth up and mic centered in mouth).

Bosso
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post #438 of 448 Old 08-20-2011, 05:43 PM - Thread Starter
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Quote:
Originally Posted by bossobass View Post

Just doing some catching up and noticed this post. Since I was reading through, I remembered this post before it:



It seems likely that your mic was exactly 1/4 wave distance from the floor (33-34") for your close mic graph and otherwise for the measurements that show no null at 100 Hz.

Without the dimensions, I'm just taking a probability stab at this. Maybe you can verify the distance of the mic-to-floor dimension in the 100 Hz null measurement vs the non-100 Hz null measurements?

To verify if this is the case, you could repeat the exercise (measure one with mouth up and mic centered in mouth).

Bosso


Well....That is a possibility I guess. I am stabbing at the distance from the floor to the mic but it was probably around 40 to 45". I wouldn't expect the reflection to cause that strong of a cancellation but maybe so. I also had a thought about a reflection from the mouth back into the horn which would also be 45" or so. I only plan to do one more test on these that requires me to drag one outdoors. If I remember I will try to check this again. Right now these are under JBL 4675-c's which aren't too easy to lift down off of them.
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post #439 of 448 Old 08-21-2011, 11:12 AM
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Quote:
Originally Posted by Ricci View Post

Mike,
The program runs under a software package called IgorPro. Powerful and very deep software for audio. It is sort of like a measurement and graphical presentation tool kit. What I mean by that is it is sort of open for the user to set up routines or experiments or setup what you want to do. It is $600 for a license if I remember right. The experiment that runs this was created by Don Keele. It is not available for purchase anywhere still. You would also need some other minimum equipment to run it foremost being an SPL calibrator.

Hmmmm, that looks like some seriously COOL software. Unfortunately, the price tag and limited availability sorta puts it out of my league.... I don't think I have invested $600 for all of my acoustic measurement gear, including the laptop.

Maybe I can grab some spectrum screengrabs in REW and overlay the CEA2010 limits? I'll have to look into alternatives. Shipping them down to you for testing might get a little expensive, not to mention placing more of a burden on you (which is just uncool....). I would like to know how my designs measure up, and CEA2010 is as good a standard as any.
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post #440 of 448 Old 08-21-2011, 11:38 AM
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Maybe John Mulcahy can add it to REW? He has added nearly everything else....REW is a powerhouse....

JSS
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post #441 of 448 Old 08-21-2011, 11:52 AM
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That would be awesome. I guess I could make that request. I have already generated some cosine-gated CEA test tones with GoldWave using the instructions from Linkwitz's site.

Working on tabulating the thresholds. I think I can actually do this with Excel and the SPL measurement tools I have already if I can get a FRD-style text dump of a spectrum measurement.

Edit - and--- it looks like I can from REW.

Will post results as soon as I get this sorted.
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post #442 of 448 Old 08-21-2011, 12:37 PM
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Quote:
Originally Posted by maxmercy View Post

Maybe John Mulcahy can add it to REW? He has added nearly everything else....REW is a powerhouse....

JSS

Done.

We'll see if this goes anywhere.
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post #443 of 448 Old 08-21-2011, 04:57 PM - Thread Starter
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Good luck Mike but I am not sure how close the results would be. There has been significant differences shown between even the "official" setup used by different parties. I tried to use ARTA and a peak hold setup to capture something similar previously and that was just not the same. Some of the results were quite close and others were way off between the 2 different ways. If you want to try I would suggest getting the signal correct first. Good luck!
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post #444 of 448 Old 10-03-2011, 10:13 AM - Thread Starter
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Might as well throw this in here. This is the new format for CEA2010 results I will be using.



Attachment 224382
Attachment 224383
LL
LL
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post #445 of 448 Old 12-13-2011, 05:01 AM
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Ricci what kind of Hpas would be needed for this sub if used in a home with a Pi18?

I doubt anyone would ever need a Hpas in a home environment but I wanted to ask. I have been looking at maybe getting a pair of the Pi18's and building a monster like this would be a good way for me to finally be able to hear which I would like to have. (Pi18 sealed or TH)

And should I send you a PM for the plans when closer to a build?

Thanks
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post #446 of 448 Old 12-13-2011, 07:12 AM
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Quote:
Originally Posted by lilmike View Post


Done.

We'll see if this goes anywhere.

How will you track tonebursts with the spectrum function? Is there a peak hold that can be used as the tonebursts play?

For steadystate tones, this ROCKS.

All we need now is to be able to track distortion components in REW like HolmImpulse can....

JSS
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post #447 of 448 Old 12-13-2011, 08:40 AM - Thread Starter
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Quote:
Originally Posted by maxmercy View Post

For steadystate tones, this ROCKS.

All we need now is to be able to track distortion components in REW like HolmImpulse can....

JSS

Agreed. I mentioned this to John long ago. If he can get harmonic distortion measurements during the sweeps implemented that would be huge for me. I use ARTA for that now. STEPS is great but way too brutal for high power. The other thing that I asked him about was beefing the generator up even further and allowing multiple sine wave output. Similar to NCH tone generator. Also the ability to do ascending or descending sweeps for measurements would be cool. REW has come a long, long way already.
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post #448 of 448 Old 12-13-2011, 08:43 AM - Thread Starter
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Quote:
Originally Posted by chrapladm View Post

Ricci what kind of Hpas would be needed for this sub if used in a home with a Pi18?

I doubt anyone would ever need a Hpas in a home environment but I wanted to ask. I have been looking at maybe getting a pair of the Pi18's and building a monster like this would be a good way for me to finally be able to hear which I would like to have. (Pi18 sealed or TH)

And should I send you a PM for the plans when closer to a build?

Thanks

Something near 14Hz and 18 or 24dB octave roll off would be recommended.

Sure.
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