Need help, designing TH sub with 2x12" drivers.

[Join]

Hey!

Got a couple of trial WT2 attempts..

Do this look correct?

 

[Join]

Latest Hornresp attempt, with new parametres.

If I set Hipass x-over at 50Hz, it will cut some on the peak in that area?

 

[littlemike]

Hey!

Got a couple of trial WT2 attempts..

Do this look correct?

Sd is not right.

12's should be around 500 cm^2 each. Be sure that you measure the diameter across the cone from the middle of the surround.

BL looks high too.

 

[littlemike]

Latest Hornresp attempt, with new parametres.

If I set Hipass x-over at 50Hz, it will cut some on the peak in that area?

Make L45 longer, the dip should fill in.

Get the measurements right first though.

 

[ravslanka]

Hey!

Got a couple of trial WT2 attempts..

Do this look correct?

hi join,

look at bl=42 and mms=947g are they ok or its just typo error.


regards

ravs



be a vegeterian.......

 

[NEO Dan]

Hey!

Got a couple of trial WT2 attempts..

Do this look correct?

You need to correct the SD and measure again

 

[Join]

You need to correct the SD and measure again

I measured SD to be 460 now. Need to find where to input the new SD value in WT2, and retry, but I'm out of time today..

Thanks guys!

 

[Join]

Hi!

Fixed SD and Mms issues.

VAS test results Coil 1 2Ohms:

Vas Efficiency completed: Mon Sep 10 13:45:36 2007
Drive level 100.00% [3181.82 uA]
;------------------------------------------------------------------
Re = 1.5986 ohms
Fs = 31.2261 Hz
Zmax = 13.7393 ohms
Qes = 0.7666
Qms = 5.8218
Qts = 0.6774
Le = 0.8488 mH (at 1 kHz)
Diam = 242.0000 mm ( 9.5276 in )
Sd =45996.0587 mm^2( 71.2940 in^2)
Vas = 48.3141 L ( 1.7062 ft^3)
BL = 8.1313 N/A
Mms = 161.5980 g
Cms = 160.7564 uM/N
Kms = 6220.5933 N/M
Rms = 5.4459 R mechanical
Efficiency = 0.1803 %
Sensitivity= 84.5781 dB @1W/1m
Sensitivity= 91.5715 dB @2.83Vrms/1m
Krm = 2.566E-03 ohms Freq dependent resistance
Erm = 816.866E-03 Rem=Krm*(2*pi*f)^Erm
Kxm = 19.259E-03 Henries Freq dependent reactance
Exm = 635.826E-03 Xem=Kxm*(2*pi*f)^Exm
;------------------------------------------------------------------

Test results Coil 2 2Ohms:

Vas Efficiency completed: Mon Sep 10 13:45:36 2007
Drive level 100.00% [3181.82 uA]
;------------------------------------------------------------------
Re = 1.5614 ohms
Fs = 31.1929 Hz
Zmax = 13.6158 ohms
Qes = 0.7415
Qms = 5.7244
Qts = 0.6565
Le = 0.7904 mH (at 1 kHz)
Diam = 242.0000 mm ( 9.5276 in )
Sd =45996.0587 mm^2( 71.2940 in^2)
Vas = 46.8810 L ( 1.6556 ft^3)
BL = 8.2994 N/A
Mms = 166.8932 g
Cms = 155.9878 uM/N
Kms = 6410.7568 N/M
Rms = 5.7140 R mechanical
Efficiency = 0.1803 %
Sensitivity= 84.5781 dB @1W/1m
Sensitivity= 91.6739 dB @2.83Vrms/1m
Krm = 2.506E-03 ohms Freq dependent resistance
Erm = 824.574E-03 Rem=Krm*(2*pi*f)^Erm
Kxm = 25.654E-03 Henries Freq dependent reactance
Exm = 592.478E-03 Xem=Kxm*(2*pi*f)^Exm
;------------------------------------------------------------------


Combined at 4Ohms will be up in a while..



EDIT:

Test results Combined Coils @ 4Ohms:

Vas Efficiency completed: Mon Sep 10 13:45:36 2007
Drive level 100.00% [3181.82 uA]
;------------------------------------------------------------------
Re = 3.1284 ohms
Fs = 30.7563 Hz
Zmax = 49.0480 ohms
Qes = 0.3177
Qms = 4.6628
Qts = 0.2974
Le = 3.1696 mH (at 1 kHz)
Diam = 242.0000 mm ( 9.5276 in )
Sd =45996.0587 mm^2( 71.2940 in^2)
Vas = 20.9521 L ( 0.7399 ft^3)
BL = 27.0369 N/A
Mms = 384.1056 g
Cms = 69.7142 uM/N
Kms =14344.2754 N/M
Rms = 15.9190 R mechanical
Efficiency = 0.1803 %
Sensitivity= 84.5781 dB @1W/1m
Sensitivity= 88.6558 dB @2.83Vrms/1m
Krm = 9.843E-03 ohms Freq dependent resistance
Erm = 824.050E-03 Rem=Krm*(2*pi*f)^Erm
Kxm = 150.957E-03 Henries Freq dependent reactance
Exm = 553.210E-03 Xem=Kxm*(2*pi*f)^Exm
;------------------------------------------------------------------

Do my test results look reasonable now?


Thanks..

 

[Join]

Make L45 longer, the dip should fill in.

I've now increased L45 to 100cm, more or less make things worse. Still problems with the peak from 45Hz to 60Hz.

Get the measurements right first though.

Hope they are good now.

look at bl=42 and mms=947g are they ok or its just typo error.

Just general errors due to lack of knowledge.. BL=27,04 still is way off from factory spec of BL=11,99. Is it correct? I guess it can be because of running the VC's i series.

 

[littlemike]

I've now increased L45 to 100cm, more or less make things worse. Still problems with the peak from 45Hz to 60Hz.



Hope they are good now.



Just general errors due to lack of knowledge.. BL=27,04 still is way off from factory spec of BL=11,99. Is it correct? I guess it can be because of running the VC's in series.

Ding ding ding ding - Winner!!!

 

[littlemike]

I've now increased L45 to 100cm, more or less make things worse. Still problems with the peak from 45Hz to 60Hz.



Hope they are good now.



Just general errors due to lack of knowledge.. BL=27,04 still is way off from factory spec of BL=11,99. Is it correct? I guess it can be because of running the VC's i series.

Try messing with the length and the taper rate. With an Fs of 30, 20 Hz should be within reach.

 

[Join]

Try messing with the length and the taper rate. With an Fs of 30, 20 Hz should be within reach.

Haha, winner!

Well, this horn model got a bit strange.... I'm not a believer of me designing a 20Hz one!

Within 3db.. One strange looking horn, not even sure it's possible to build due to the VERY long L45! With this model the large 70Hz dip is gone.

But, my measurements look OK now?

 

[littlemike]

Things look a lot better. If I have the time today, I'll mess with your measured parameters a bit and see if I can do any better.

 

[Join]

Here's my latest Hornresp attempt.

Man, this horn is really growing in size for the last few Hz's downwards! And I'm not sure how easy it is to design a horn like this.

Hmm.. How to do this with a very musical result...

 

[littlemike]

I have played with your measured specs a bit, and I am not having any better luck than you are.

One thing I have learned recently - was the driver tested at room temperature? Cold surrounds are less flexible than warm ones which threw my latest measurements off by quite a lot.

 

[Join]

I have played with your measured specs a bit, and I am not having any better luck than you are.

One thing I have learned recently - was the driver tested at room temperature? Cold surrounds are less flexible than warm ones which threw my latest measurements off by quite a lot.

Yeah, something bad happens when fixing another problem.. Alot Of Tradeoffs..


Yes, it was. I was reading something in the WT2 user manual about new drivers, and they was recommended to run a run-in period of a certain amount of hours at the drivers FS, using WT2's line out option through a external amp.

My driver isn't new, but it have been sitting 4years or so. Might be a good idea to do it? Set the frequency at 30Hz and let it run at some load for 12hours? Got no rig or box for it, might limit the powerlevel..

 

[littlemike]

Actually - breaking in a driver is better when done outside of an enclosure. It is much quieter, it takes less power, and the driver tends to be cooled better.

Couldn't hurt to try.

 

[Join]

Actually - breaking in a driver is better when done outside of an enclosure. It is much quieter, it takes less power, and the driver tends to be cooled better.

Couldn't hurt to try.

When testing, I've just put the driver with it's magnet directly to the floor, but that will restrict any air from the inside of the cone through the Baffled vent hole in the magnet. Will that effect a reading?

Also, after I run a "break-in" on the driver, should the test be ran just after, or let it cool a bit first?

thanks

 

[Join]

Hi!

My driver is now running at 20Hz, was really just plug and play to get the line signal. Just enter 30Hz and Enter.

I got a problem running the drivers FS, 30Hz looks like it's the frequency that trigger my wife's nerves!

it shouldn't be a problem running 20hz?

I'm using the amp for the Paradigm PS1000 sub for this "run-in" setup.
The power supply is rated at 150VA. Is that suficcient for my project until I can afford the one I want?

 

[Join]

Hi!

New measurements:

Vas Efficiency completed: Mon Sep 10 13:45:36 2007
Drive level 100.00% [3181.82 uA]
;------------------------------------------------------------------
Re = 3.1995 ohms
Fs = 30.2057 Hz
Zmax = 49.2008 ohms
Qes = 0.3265
Qms = 4.6949
Qts = 0.3053
Le = 3.1724 mH (at 1 kHz)
Diam = 242.0000 mm ( 9.5276 in )
Sd =45996.0587 mm^2( 71.2940 in^2)
Vas = 22.7363 L ( 0.8029 ft^3)
BL = 26.1235 N/A
Mms = 366.9832 g
Cms = 75.6510 uM/N
Kms =13218.5898 N/M
Rms = 14.8352 R mechanical
Efficiency = 0.1803 %
Sensitivity= 84.5781 dB @1W/1m
Sensitivity= 88.5583 dB @2.83Vrms/1m
Krm = 9.913E-03 ohms Freq dependent resistance
Erm = 823.167E-03 Rem=Krm*(2*pi*f)^Erm
Kxm = 138.668E-03 Henries Freq dependent reactance
Exm = 562.298E-03 Xem=Kxm*(2*pi*f)^Exm
;------------------------------------------------------------------

I'm going to play a little more with Hornresp tonight, hopeefully with better results..