TH-18 Flat to 35hz! (Xoc1's design) - Page 116 - diyAudio
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Old 16th October 2012, 03:01 AM   #1151
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Hi Xoc1,
I do need some help and I realize time is precious to all of us,Now I built the 1st box acording to #6 thread plans is this a mk1? I also built a second box I call it #2 it has cone correction incoporated in the folds,did this with a big protractor and followed the flow of the folds,My question is could I get you to model it and tell me where I'm at at S1 as far as I know right now both sides are equal ,I would think S1 needs to be smaller but I am not a cad or hornresp designer,I'm learning but neither are quick learning curves ,lol. I wished, but alot of varibles,so any suggestion,I am listening,I have the first box running good with the additions to the stubs with rings ,pics in the earlier threads,
I hope you are recovering well,I would have asked you earlier but I know first hand about recoveries and didn't want to burden you ! Glad you're Better!Email if you like!
Regards,
NS
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Old 16th October 2012, 04:03 AM   #1152
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Quote:
Originally Posted by Xoc1 View Post
.
I see you have modded your Mk1 speakers throat with a coule of layers of 18mm timber
Did you ever manage any measurements?
What would you say was the subjective result of the throat mods?
POST #744

These measurements were taken as the amplifier just illuminated the limit light, which is WELL under the rated output power. My voltmeter does not climb quickly enough with 'Rec' engaged and caused it to go "Over" many times, so exact voltage values are unknown for that night of testing. I just used this info for comparison sake and hope to figure out my REW issue soon.

I only played/measured test tones without and with cone correction.

It appears the difference from 35Hz to 45Hz bettered (response dipped less) by 0.5dB with correction. As 45-50Hz did by 0.2dB and the 0.7dB dip @ 75Hz disappeared with correction as well.

So, we see response drops off a (small) bit more gradually while also 'fixing' very slight response issues with cone correction (I used roughly HALF of the 18SW100's cone volume for this test). For a few pieces of extra/spare timber? I'll take it!
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Old 16th October 2012, 07:02 AM   #1153
NEO Dan is offline NEO Dan  United States
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Unless you are in an open field the meter and sine waves method is not accurate.

It would be great to get an anechoic measurement.

So what is the plan of action to get that done?

Looking back at the post, you mention it was over grass. But how far away are the closest objects that can be sources of reflection? Anything bigger than a phone booth?

Does the MBP have two 1/8" audio jacks? The newer ones have only one
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Dan
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Old 16th October 2012, 07:27 AM   #1154
NEO Dan is offline NEO Dan  United States
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Dang Justin,
Your 3402 and dual 18's ain't got nothing on my:
Click the image to open in full size.




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Old 16th October 2012, 07:40 AM   #1155
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Quote:
Originally Posted by NEO Dan View Post
Unless you are in an open field the meter and sine waves method is not accurate.

It would be great to get an anechoic measurement.

So what is the plan of action to get that done?

Looking back at the post, you mention it was over grass. But how far away are the closest objects that can be sources of reflection? Anything bigger than a phone booth?
I've attached an image of the same testing configuration I used for SS15 measuring.

But, again, this was for comparison sake - cone correction vs without. Not highest-most-accurate-super-scientific-ness It was getting very late, dark and I wanted to finish the subs in time for a show. I was simply gauging the affect of the correction and if my cabs should have it.


Quote:
Originally Posted by NEO Dan View Post
Does the MBP have two 1/8" audio jacks? The newer ones have only one
It has 1/8" headphone out and 1/8" mic in.
Attached Images
File Type: jpg SS15 measurement conditions 1.jpg (555.5 KB, 585 views)
File Type: jpg SS15 measurements conditions 2.jpg (688.4 KB, 566 views)
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Old 16th October 2012, 07:45 AM   #1156
NEO Dan is offline NEO Dan  United States
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10'-15' looks like, surprised the neighbors didn't kill you.
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Old 17th October 2012, 12:27 AM   #1157
kctess5 is offline kctess5  United States
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Finally finished my time lapse

Check it out...

https://www.youtube.com/watch?v=BOwhWyn5ymE
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Old 17th October 2012, 04:37 AM   #1158
epa is offline epa  Netherlands
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Quote:
Originally Posted by kctess5 View Post
Finally finished my time lapse

Check it out...

https://www.youtube.com/watch?v=BOwhWyn5ymE
nice movie.
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Old 17th October 2012, 04:43 AM   #1159
kctess5 is offline kctess5  United States
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Quote:
nice movie.
Thanks! I think it's pretty cool... I made it in part because you can give a video link to the Massachusetts Institute of Technology, which is my top choice college that I'm applying to.

I tested the 3 of these that I have done a tiny bit today. I maxed out my SPL meter at 130 dB

I was hitting 100 dB peaks from approx 200 ft. I did the testing at lunch, and people all over the school heard it. Turns out when you hit 130dB at lunch you draw a crowd, and people tend to notice who you are haha
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Old 17th October 2012, 05:54 AM   #1160
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Hi Kctress5,
Nice build ,fasst ! too,lol.
NS
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