Is my WT3 working properly?

pp173 · 20th July 2008, 05:12 PM

Hi,

I just bought a WT3 from Parts Express. I'm trying to get better specs for my HiVi F8's than Swan has on their website. I'm getting measurements that seem correct:
Re=6.587 (Swan: 6.5)
Fs=38.36 (Swan: 36)
Le=0.6176 (Swan: ?)

I'm also getting measurements that seem to be incorrect:
Qts=0.4685 (Swan: 0.39)
Qes=0.5067 (Swan: 0.51)
Qms=6.223 (Swan: 1.73)

I've calibrated my leads and impedence. I'm testing the speaker while holding it by the sides of the magnet, away from my body - with the cone's face aimed horizontally outward.

Can something be wrong with my WT3? I'm *very* new. Does this seem to indicate a problem with the driver? Its' twin gets very similar readings.

I'm not sure how else I can test my WT3. I can compare results of driver measurements with someone. Laying around for measurement, I have:
Vifa D 19 TD-5 tweeter
Morel MDT-20 tweeter

Or, could someome recommend a procedure who's results I can compare to for normalization?

Thanks!
Peter

freddi · 20th July 2008, 05:21 PM

do you have your mixer gains up all the way?

pp173 · 20th July 2008, 05:23 PM

freddi,

Thanks for the response. Yes - and the balance is centered. And, the audio for record is set to 2 channel, 16-bit, 44.1Khz.

Peter

Pano · 20th July 2008, 06:53 PM

Everything but Qms looks right on. (and that throws off Qts).

Don't know why it would be so far off. Most of the drivers I've done with the WT3 have a variance from spec of Qms, but not that large!

Are you getting the effective diameter right? (or does that matter for the Qms calc?)

pp173 · 20th July 2008, 08:02 PM

panomaniac,

I think it's only for Vas measurements.

sreten · 22nd July 2008, 11:38 AM

Hi,

Like I said your measurements are consistent. Qes is near enough
not to worry. The different Qms are causing the Qts differences.

Qms is impossible to sanity check unless it is far too small or large.
Values of 1 to >10 are possible, 1.5 to 7 typical. The F6 according
to Zaph has Qms = 5.4, assuming its made the same way as the
F8 moreorless I would tend to suspect the Qms = 1.7 specification.

/sreten.

P.S. Sd only really matters in calculating Mms (for a given Vas).

pp173 · 22nd July 2008, 02:39 PM

Thanks Sreten!

I'm not sure if you checked out my latest addition to my original post, but I'm sum it up. The numbers I gathered suggested an enclosure very similar to one of the ones I had experimented with (but with dual 2" ports). I tried this - and I'm starting to believe the measurements, because the sound smoothed out overall. There's very little harshness left coming from the woofer - and what is (I think) is most likely because I have no dampening material on the sides of the cabinet (just a prototype).

Now I need to learn how to import the impedance data into Winspeakerz. Is there a howto? I'd like to start plugging in potential crossover characteristics and model some different tweeters.

Thanks again!
Peter

20th July 2008, 05:12 PM	#1
pp173 diyAudio Member Join Date: Jul 2008	Is my WT3 working properly? Hi, I just bought a WT3 from Parts Express. I'm trying to get better specs for my HiVi F8's than Swan has on their website. I'm getting measurements that seem correct: Re=6.587 (Swan: 6.5) Fs=38.36 (Swan: 36) Le=0.6176 (Swan: ?) I'm also getting measurements that seem to be incorrect: Qts=0.4685 (Swan: 0.39) Qes=0.5067 (Swan: 0.51) Qms=6.223 (Swan: 1.73) I've calibrated my leads and impedence. I'm testing the speaker while holding it by the sides of the magnet, away from my body - with the cone's face aimed horizontally outward. Can something be wrong with my WT3? I'm very new. Does this seem to indicate a problem with the driver? Its' twin gets very similar readings. I'm not sure how else I can test my WT3. I can compare results of driver measurements with someone. Laying around for measurement, I have: Vifa D 19 TD-5 tweeter Morel MDT-20 tweeter Or, could someome recommend a procedure who's results I can compare to for normalization? Thanks! Peter

20th July 2008, 06:53 PM	#4
Pano diyAudio Moderator Join Date: Oct 2004 Location: North Carolina Blog Entries: 4	Everything but Qms looks right on. (and that throws off Qts). Don't know why it would be so far off. Most of the drivers I've done with the WT3 have a variance from spec of Qms, but not that large! Are you getting the effective diameter right? (or does that matter for the Qms calc?) __________________ Take the Speaker Voltage Test!

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20th July 2008, 05:21 PM	#2
freddi diyAudio Member Join Date: Aug 2005	do you have your mixer gains up all the way?

20th July 2008, 05:23 PM	#3
pp173 diyAudio Member Join Date: Jul 2008	freddi, Thanks for the response. Yes - and the balance is centered. And, the audio for record is set to 2 channel, 16-bit, 44.1Khz. Peter

20th July 2008, 08:02 PM	#5
pp173 diyAudio Member Join Date: Jul 2008	panomaniac, I think it's only for Vas measurements.

22nd July 2008, 11:38 AM	#6
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Like I said your measurements are consistent. Qes is near enough not to worry. The different Qms are causing the Qts differences. Qms is impossible to sanity check unless it is far too small or large. Values of 1 to >10 are possible, 1.5 to 7 typical. The F6 according to Zaph has Qms = 5.4, assuming its made the same way as the F8 moreorless I would tend to suspect the Qms = 1.7 specification. /sreten. P.S. Sd only really matters in calculating Mms (for a given Vas).

22nd July 2008, 02:39 PM	#7
pp173 diyAudio Member Join Date: Jul 2008	Thanks Sreten! I'm not sure if you checked out my latest addition to my original post, but I'm sum it up. The numbers I gathered suggested an enclosure very similar to one of the ones I had experimented with (but with dual 2" ports). I tried this - and I'm starting to believe the measurements, because the sound smoothed out overall. There's very little harshness left coming from the woofer - and what is (I think) is most likely because I have no dampening material on the sides of the cabinet (just a prototype). Now I need to learn how to import the impedance data into Winspeakerz. Is there a howto? I'd like to start plugging in potential crossover characteristics and model some different tweeters. Thanks again! Peter