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September 20th, 2012, 10:48 PM
#1
Senior Hostboard Member
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September 20th, 2012, 11:22 PM
#2
Senior Hostboard Member
Re: Broke down. Got a duplex.
Cool. Let us know how it is when it gets back from Oklahoma.
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September 21st, 2012, 09:15 AM
#3
Senior Hostboard Member
Re: Broke down. Got a duplex.
Nice! Please keep us posted. I'll bet that speaker sounds amazing after you get it back from Bill/GPA. BTW, I'm inventing a triplex speaker. Altec 15" Biflex woofer with h.f. driver/horn (not to be confused with a triflex?)....
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September 21st, 2012, 02:18 PM
#4
Senior Hostboard Member
Re: Broke down. Got a duplex.
Congrats
Welcome to the Duplex family
Are your magnets alnico or ceramic
I noticed the woofer R is about 7 Ohms. I expected to see about 12. What V.C. Are you getting on the new GPA?
Don
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September 21st, 2012, 05:21 PM
#5
Senior Hostboard Member
Re: Broke down. Got a duplex.
Ummmm,
I got it back from GPA yesterday - those measurements reflect the "GPA treatment"...
It's a huge mother - 604E so it's Alnico.
And yes, Don, I expected the same thing from the woofer VC - Bill told me he was putting in 16 ohm VCs for both HF and LF...
I only had time last night to very briefly hook it up through the Behringer dcx2496, as I don't have a XO for it yet. No cabinet either. It sounded...meh. The mids were very clear, and I think I got a glimpse of what everyone talks about that "point-source" sound - some extremely revealing details from the recordings, but as you'd expect I guess from an unmounted speaker it was utterly lacking any low end. I need to throw together a passive XO (plan to use Markwarts design as a starting point). But it is curious that the Woofer R is reading like an 8ohm VC is in there. Some of the other T/S params match very well with what is posted on Todd's list, while others are off by quite a bit. Does the MM number look right? I thought it was curious that DATS came back with a number that essentially equaled the amount that I applied to the cone to calculate the Vas. The math for that doesn't work out...
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September 21st, 2012, 05:34 PM
#6
Senior Hostboard Member
Re: Broke down. Got a duplex.
Ah, those are after - sorry! I'd say Mms looks low, that's a light cone. But I'm not sure. I'll see if I can dig up files on some GPA reconed 604s (ferrite) I had here.
From the plot, it looks like an ohm woofer and horn to me.
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September 22nd, 2012, 09:54 AM
#7
Senior Hostboard Member
Re: Broke down. Got a duplex.
Originally Posted by
AlienShore
I gave in and picked up a beat up 604E. Sent it off to Bill to have him give it the GPA treatment.
From your measurements, it appears the "GPA treatment" is to turn a 16 ohm 604 into a 10 ohm 605 ( if that DAT measurement is to be believed ) .
Time will tell if your measurements hold water ( fyi, others using WT3, which was the G1 version of DATS , had many problems with it, maybe DATS is better ??? ) .
The current measurements tune up quite well ( if accurate ) using a 9.5 cu' enclosure tuned to 25hz .
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September 23rd, 2012, 06:29 PM
#8
Senior Hostboard Member
Re: Broke down. Got a duplex.
Originally Posted by
Earl K
From your measurements, it appears the "GPA treatment" is to turn a 16 ohm 604 into a 10 ohm 605 ( if that DAT measurement is to be believed )
Yep - that's what it looks like. I sent GPA an email - we'll see if they reply.
In the meantime, do you recommend another (more reliable) method for testing T/S?
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September 23rd, 2012, 09:11 PM
#9
Senior Hostboard Member
Re: Broke down. Got a duplex.
WT2 is more reliable than WT3/DATS ( different maker with a different way of measuring ) .
REW has a TS parameter measurement area ( you need to wire-up a small box ) that uses the same method as WT3 .
Personally, I wouldn't bother GPA with this type of thing until you've gotten similar measurements from at least one other measuring program.
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September 24th, 2012, 07:31 AM
#10
Senior Hostboard Member
Re: Broke down. Got a duplex.
- Every once in a while it is worth the diy hobbyists time to check ( recalibrate ) the validity of ones measurements by using another method ( really , it's simply part of the scientific method ).
- For TS parameters ( when checking these "all-in-one" devices ) one can use the old standby method outlined here !
- I believe that verifying Re, Fs & Qts ( Qms, Qes ) is enough to know where ones device stands .
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