- Feb 16, 2008
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- John K Custom Basses
just for the fun of it i did a little quick and dirty pink noise RTA tests between the 3015's and 15PR400's and here's what they looked like:
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Custom DIY 2x15 cab build
- Thread starter johnk_10
- Start date
http://www.usspeaker.com/Kappa Lite-3015-1.htm
http://www.usspeaker.com/faital pro 15PR400-1.htm
Comparing the graphs Eminence and Faital provides with yours, the Faital seems to line up more like you'd expect, while the Eminence looks more smoothed out, especially that ganky 1.5k peak that shows up in Eminence's graph.
http://www.usspeaker.com/faital pro 15PR400-1.htm
Comparing the graphs Eminence and Faital provides with yours, the Faital seems to line up more like you'd expect, while the Eminence looks more smoothed out, especially that ganky 1.5k peak that shows up in Eminence's graph.
Right before you wrote this I was going to ask if you've tried mixing the 3015 and the Faital in the same cabinet. Since they are pretty close it might work.
- Feb 16, 2008
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- John K Custom Basses
i agree. i thought exactly the same thing when i saw it. fortunately the 3015 doesn't sound as 'peaky' at 1.8-2Khz like their chart shows when playing thru my cab, and it didn't sound peaky in that range on the full-range Steeley Dan 'do it again' recordings i posted earlier in this thread either.
I've noticed that with a few eminence drivers, my DLII2512's being one. The peak in that chart looks like my ears couldn't stand it, but they sound nice. There is a little bit of something going on there, but doesn't sound like how it looks. I can only assume it's to do with being tested sort of free air, or mounted in a wall baffle at the end of a chamber/room and being used in the cab. Measured cab RTA's I've seen don't have the high peak the datasheet does.
Listening to other drivers like Avatars "LF" spinoffs of the deltalite where that peak would come lower, say 1500hz instead of 2500, those the peak really stands out...in the cab and my ears don't like those. Then they do sound clanky/peaky, etc. to me. Similair with 18's that are a little more "instrument" drivers and not subwoofer only jobs. Another instance where the peak would come a bit lower in frequency.
Listening to other drivers like Avatars "LF" spinoffs of the deltalite where that peak would come lower, say 1500hz instead of 2500, those the peak really stands out...in the cab and my ears don't like those. Then they do sound clanky/peaky, etc. to me. Similair with 18's that are a little more "instrument" drivers and not subwoofer only jobs. Another instance where the peak would come a bit lower in frequency.
It would have to be to some degree but mostly on the lower end of the chart. If he did it outside, it's more of a true halfspace measurement. Even then it's hard to get accurate results in the bottom. The model will be pretty accurate down there. To get a real good mic measurement, you have to take a ground plane measurement up to 100hz or so and graft that onto the 1 meter centered mic position for the rest.
Of course, just taking a measurement wherever you're playing the cab would show you what it sounds like in that place, in that room.
I did a series of sessions in an anechoic chamber and the effect of not having reflections was dramatic.
Performing the test with the cab outside might provide an interesting comparison. At the very least, it might keep the neighborhood cats off the property.
Performing the test with the cab outside might provide an interesting comparison. At the very least, it might keep the neighborhood cats off the property.
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i'm sure that it does a bit, and these are anything but under a controlled environment, so they're basically 'relative'. i mic'd the cabs pretty close too at only 8" so that the room wouldn't enter into it as much as if i mic'd them at 1 meter, and when i cranked it up louder to maintain the same level and moved the mic further away, it really didn't change the response reading very much.
- Feb 16, 2008
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and i agree with will33 on the 21512 II's. mine don't sound anywhere near as mid heavy/peaky as the eminence charts would indicate.
- Feb 16, 2008
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I did a series of sessions in an anechoic chamber and the effect of not having reflections was dramatic.
Performing the test with the cab outside might provide an interesting comparison. At the very least, it might keep the neighborhood cats off the property.
if i get a chance tomorrow, i'll take the cabs outside and see what they look like. i guess laying the cab on it's back and suspending the mic above it at 1M would yield the most accurate results.
Moving the mic and checking the response changes was a good way to set up the tests. If you close mic your cabs when you play I would think that your test would be a good indicator of what to expect.
if you look at the eminence website you can see that every bass driver they test has a huge peak at 2k hz
probably has something to do with the 2ftx2ft baffle they mount the drivers on to test...or their room...
but it seems pretty consistent with their bass drivers
http://www.eminence.com/guitar-bass/bass-guitar/
also if you read the text at the bottom of the pdf spec sheet it states how they test their drivers
probably has something to do with the 2ftx2ft baffle they mount the drivers on to test...or their room...
but it seems pretty consistent with their bass drivers
http://www.eminence.com/guitar-bass/bass-guitar/
also if you read the text at the bottom of the pdf spec sheet it states how they test their drivers
Most likely. If ya wanna get all technical about it, you dig a hole so the cones are even with the ground. Effectively eliminates the baffle step and the cancellation distance due to the depth of the cab but that's a lot of work.
Any measurement you do outside would still be telling of the different things rooms can do to us. If you want, you can run 2 sweeps. One with the mic literally an inch off the ground and one centered on the cab. The ground plane one would get a more representative measurement of your lowend out there. No shovel required.
...but that's a lot of work.
but what will Mrs johnk_10 say if there is a hole in the front lawn ?
Come to think of it, what will the neighbours think, when you're digging a coffin sized hole in your lawn ....
johnk_10, thanks for those RTA's great stuff, much appreciated
- Feb 16, 2008
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i was just going to say that there's no way that i'm going to be digging a coffin sized hole in my backyard. 
IOW, it'll have to be an above ground test.
IOW, it'll have to be an above ground test.
You may be on to something there, I've never bothered to reverse engineer it all. The Legend CB158 is another one that doesn't sound like the graph looks on the top end. I've just come to somewhat ignore the peaks if they come above 2 khz and shy away from the when they come below 2 khz. May not be on the right path technically, but it makes the difference in what my ears like/don't like. Bi-amping to a mid, those peaks are a non-issue anyway, but I still like how my stock spec deltalites sound run full range, if you don't need the extra top or dispersion the 6 gives.
i was just going to say that there's no way that i'm going to be digging a coffin sized hole in my backyard.
IOW, it'll have to be an above ground test.
Certainly wouldn't expect you to....that was posted pretty late.
The mic at almost ground level would be interesting to compare though. It's the "proper" way acoustically, but I don't think I've ever seen the 2 mic position measurements individually before they were grafted together.
