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Old 20th March 2006, 10:52 PM   #1
mazurek is offline mazurek  United States
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Default postmortem of loudspeaker project

I just wrote a huge write up of my speaker project. Dayton 12HF - Peerless 83075, Seas 27TDFC, active crossover.

http://www.mazprojects.com/audio/

Please comment, any newbies here should be able to learn something from it, veterans give me your opinion.
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Old 20th March 2006, 11:08 PM   #2
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Default Re: postmortem of loudspeaker project

Looks good, well done

Just one small thing... some of the pictures don't show at the moment but other than that they look great and I bet you've got plenty of bass with those 2 x 12" DREF's.
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Old 20th March 2006, 11:17 PM   #3
cotdt is offline cotdt  United States
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the pictures don't work on the site

i think using the peerless exclusives would be an improvement.

you can fix the room reflection issues by moving the speakers outdoors.
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Old 20th March 2006, 11:35 PM   #4
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Quote:
Originally posted by cotdt
the pictures don't work on the site
Already been mentioned

Quote:
i think using the peerless exclusives would be an improvement.
Irrelevant.

Quote:
you can fix the room reflection issues by moving the speakers outdoors.
What a really helpful comment. I suspect he'd never thought of that.
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Old 20th March 2006, 11:37 PM   #5
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Quote:
Originally posted by pinkmouse

What a really helpful comment. I suspect he'd never thought of that.


Perhaps we can put cotdt outside and this thread would sound better?
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Old 20th March 2006, 11:50 PM   #6
mazurek is offline mazurek  United States
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Thanks for the notice, I fixed the pix and checked on another computer. Need to get a better page editor.

I'll just work now on moving to the equator so I can live with my speakers outside.

I may play with the hds exclusive to see if it can get closer to xmax without distortion, if I had the money I'd play with the skaaning sk170.
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Old 21st March 2006, 12:40 AM   #7
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They are working now mazurek.

I must say that looking at the response graphs for the 12" DREF's, I thought there'd be more low end output. They look to have a -3dB of around 40hz. I assume from the roll off reate that these are sealed enclosures?

Do you feel that they go low enough for you at this time? Seems like you've got the potential to boost it up quite nicely with EQ and not run out of headroom easily. Or are you using a seperate subwoofer somewhere that does the really low stuff?

Just a thought related to my own rather perverted bass taste rather than anything else

EDIT:

I really should actually read the whole webpage rather than just looking at the pictures

I see you answered my question here:

"I played around with a Linkwitz transform circuit for the subwoofer, and I found that pushing the extension down to 25 Hz made the speakers more enjoyable. I will probably implement a physical one eventually, but it will reduce the volume headroom of the speakers and make them play closer to excursion limits (which is bad, you can subtly here the motor at excursion limits). Ultimately, when I get the time and money, I will go with 2 12 inch drivers per sub. I am playing them in a huge room, and donít get much of a room gain"
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Old 21st March 2006, 12:59 AM   #8
mazurek is offline mazurek  United States
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You got it ShinOBIWAN, I wasn't comfortable yet to design ported subs. They do only go down to 40 Hz. Its real clean though. I need to figure out a good way to put in a Linkwitz transform (I have a soft one set up for digital music, but nothing otherwise), I think I'll make a separate sub equalizer box, because I like the idea of keeping the subwoofer system separate from the main crossover, so I can change it or add even more subs without redoing the main crossover.

With the soft LT circuit, I would have 25 Hz as -3dB, one subwoofer should hit 101dB as displacement limit. The two are within half a wavelength so it should hit 107dB. I wouldn't say I have to have more subwoofers, but I get uncomfortable watching my subs going 1" peak to peak (I'll be so sad if I kill them). SPL meters confirm my room gets almost no gain, which is sad.
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Old 21st March 2006, 01:06 AM   #9
AJinFLA is offline AJinFLA  United States
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Quote:
Perhaps we can put cotdt outside and this thread would sound better?
I have a better idea. Lets put him on Jupiter so he can pick up some metallic hydrogen http://www.diyaudio.com/forums/showt...897#post872897
I figure we could combine cotdt's hydrometallic/crazy diamond cones with Feandil "I ruined my moms ebay account with fraudulent speaker claims" Audiophilenoob's 22mm xmax motor.
Think of the possibilities! The internet is such a wonderful place indeed! I really got my money's worth today.
BTW, cotdt, what happened to your one time absolute fascination with hemp cone drivers? That was one thing that seemed to make actual sense. Too bad. Gotta run...

cheers,

AJ

p.s. Pinkmouse, you're such a party pooper. Just when threads start drifting into the twilight zone, you intrude with reality! Shame, shame
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Old 21st March 2006, 01:23 AM   #10
cotdt is offline cotdt  United States
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I would have used the hemp drivers but already settled on a midrange. Now i'm going to mod my mids with a new cone. which will probably be diamond. but you won't be interested since all you care for are poly coned mids with coaxial tweeters.

good things are happening though! i've been doing research for future plasma tweeters which will blow everything away.

Quote:
Originally posted by AJinFLA


I have a better idea. Lets put him on Jupiter so he can pick up some metallic hydrogen http://www.diyaudio.com/forums/showt...897#post872897
I figure we could combine cotdt's hydrometallic/crazy diamond cones with Feandil "I ruined my moms ebay account with fraudulent speaker claims" Audiophilenoob's 22mm xmax motor.
Think of the possibilities! The internet is such a wonderful place indeed! I really got my money's worth today.
BTW, cotdt, what happened to your one time absolute fascination with hemp cone drivers? That was one thing that seemed to make actual sense. Too bad. Gotta run...

cheers,

AJ

p.s. Pinkmouse, you're such a party pooper. Just when threads start drifting into the twilight zone, you intrude with reality! Shame, shame
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