I sent the Zetag engineer the values posted earlier and asked if they looked right. He e-mailed me back and said all looked right except the Qms, he will get back to me on the exact numbers. But it does sound like they are definitely in the ballpark.
Fs 36.5 Hz
Qms 9.09
Qts 0.41
Qes 0.43
Vas 25.8 litres
BL 7.30
efficiency 86.8 dB 1W/1m
Fs 36.5 Hz
Qms 9.09
Qts 0.41
Qes 0.43
Vas 25.8 litres
BL 7.30
efficiency 86.8 dB 1W/1m
OK tonight I measured the woofer resistance and got 3.5 ohms on each. Also, I wrote down more of the information off the crossover parts shown in the picture posted earlier. Can I get any other information that would help figure out what is happening?
The large white cap is 10.0UF +10% - 400VDC T40
The blue cap says 15UF 50V
The green caps say BENNIC VENT NONPOLAR 24MFD 100W
The inductors say nothing and the rectangular resistor? says nothing either.
The large white cap is 10.0UF +10% - 400VDC T40
The blue cap says 15UF 50V
The green caps say BENNIC VENT NONPOLAR 24MFD 100W
The inductors say nothing and the rectangular resistor? says nothing either.
Based on the provided info, this is what I got. It appears from the modeling that this speaker has a nasty deep in the 1200hz. It also has a loooow impedance and drops down to below 2ohm. It also looks like these x-overs were put together rather in a hurry with less then perfect components.
I would just build new x-overs after you get more data from your engineers.
I would just build new x-overs after you get more data from your engineers.
Attachments
Thank you.
Like I said, it's only a predicted response based on provided components value. Fant is hearing something bad and it may be that deep in the frequency response (I am guessing again).
Real crossover design will take some hours or so and would be different for a sealed center channel and ported sides.
I also can see there his Pioneer will constantly clip from a under 2ohm impedance. Not a good thing to have.
I don't think Z tags are bad. I've never heard it or of it but I think if fed properly could be trouble free.
Lets see how it's going to work out.
Like I said, it's only a predicted response based on provided components value. Fant is hearing something bad and it may be that deep in the frequency response (I am guessing again).
Real crossover design will take some hours or so and would be different for a sealed center channel and ported sides.
I also can see there his Pioneer will constantly clip from a under 2ohm impedance. Not a good thing to have.
I don't think Z tags are bad. I've never heard it or of it but I think if fed properly could be trouble free.
Lets see how it's going to work out.
Well, finally received the Zetag specs from PartsExpress, somewhat different then first thought.
f(s) = 38.36 Hz
Q(ms) = 7.591
V(as) = 28.11 liters (0.993 cubic feet)
n(0) = 0.39 %
M(ms) = 15.24 grams
R(e) = 5.93 Ohms
Q(es) = 0.389
SPL = 88.00 dB SPL 1W/1m
C(ms) = 1.13 mm/N
Piston Diameter = 130.2 mm
Z(max) = 121.80 Ohms
Q(ts) = 0.370
L(e) = 0.78 mH
BL = 7.49
WT3
1.0.4
f(s) = 38.36 Hz
Q(ms) = 7.591
V(as) = 28.11 liters (0.993 cubic feet)
n(0) = 0.39 %
M(ms) = 15.24 grams
R(e) = 5.93 Ohms
Q(es) = 0.389
SPL = 88.00 dB SPL 1W/1m
C(ms) = 1.13 mm/N
Piston Diameter = 130.2 mm
Z(max) = 121.80 Ohms
Q(ts) = 0.370
L(e) = 0.78 mH
BL = 7.49
WT3
1.0.4
X-max would be helpful on z tags also. WT3 on the bottom, means Woofer Tester 3.
Considering tweeters, how far are your speakers from TV and I guess I am asking if you prefer shielded tweeter or unshielded. If your Ztags aren’t shielded, then you may as well go for unshielded tweeters. Either way, there’s plenty to chose from at that price range.
Just to give you an example:
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_326&products_id=793
really nice tweeter. For the money I didn’t expect quite the resolution that it has.
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_326&products_id=1082
Never heard this one but perhaps someone else on this forum did.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=275-135
I heard this one in my friend’s system. He used 2nd order l-r x-over and crossed it over right at FS. I didn’t like it too much but perhaps with 3rd or 4th order x-over it would be excellent.
Now unshielded:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=277-030
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-555
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_324&products_id=792
Considering tweeters, how far are your speakers from TV and I guess I am asking if you prefer shielded tweeter or unshielded. If your Ztags aren’t shielded, then you may as well go for unshielded tweeters. Either way, there’s plenty to chose from at that price range.
Just to give you an example:
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_326&products_id=793
really nice tweeter. For the money I didn’t expect quite the resolution that it has.
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_326&products_id=1082
Never heard this one but perhaps someone else on this forum did.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=275-135
I heard this one in my friend’s system. He used 2nd order l-r x-over and crossed it over right at FS. I didn’t like it too much but perhaps with 3rd or 4th order x-over it would be excellent.
Now unshielded:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=277-030
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-555
http://www.madisound.com/catalog/product_info.php?cPath=45_229_270_324&products_id=792
Do the specs on the Zetags make better sense now?
The guy from Parts Express said he thought it was very well made. Of course he didn't listen to it he only measured it with the tester.
As far as shielded tweeters go, only the center channel is within 4' of the TV. The Zetags are shielded so it probably makes sense to just go with a shielded tweeter. The tech from PE suggested the Vifa, 27TG but of course they don't sell Seas products.
Is there a difference in the drivers that are shielded vs non shielded other then the shielding?
The guy from Parts Express said he thought it was very well made. Of course he didn't listen to it he only measured it with the tester.
As far as shielded tweeters go, only the center channel is within 4' of the TV. The Zetags are shielded so it probably makes sense to just go with a shielded tweeter. The tech from PE suggested the Vifa, 27TG but of course they don't sell Seas products.
Is there a difference in the drivers that are shielded vs non shielded other then the shielding?
It would be hard to evaluate the driver without putting it in to enclosure and building a crossover network, which would give different results with multitude of different driver couplings.
So again, “do u like it?” is a purely subjective question. What if someone tells you, “no, I think it sounds like a dog sh..t!” Or the other way around, “it’s unbelievably detailed and neutral in the character!”. Well, how did you listen, on the infinite baffle?
He just measured the driver and expressed his opinion of a build quality, which apparently is nice.
Specs make sense. Again, x-mass would also help.
Vifa 27TG looks like a very good tweeter. XT 25 is much more linear and I know that some people went ape-sh..t from the apparently great performance. It is also twice the money of 27GT.
I don’t think performance of the tweeter is greatly distorted by shielding, the back of the tweeter is sealed anyway, but I am not an expert at all in this area.
4 inches may be too close to use unshielded version. In addition, as far as HT gurus tell us, tweeter in front channels should be the same as the one in the center channel.
I have build 2 HT systems, with different tweeters and on the contrary to this believe, had no problems at all.
So again, “do u like it?” is a purely subjective question. What if someone tells you, “no, I think it sounds like a dog sh..t!” Or the other way around, “it’s unbelievably detailed and neutral in the character!”. Well, how did you listen, on the infinite baffle?
He just measured the driver and expressed his opinion of a build quality, which apparently is nice.
Specs make sense. Again, x-mass would also help.
Vifa 27TG looks like a very good tweeter. XT 25 is much more linear and I know that some people went ape-sh..t from the apparently great performance. It is also twice the money of 27GT.
I don’t think performance of the tweeter is greatly distorted by shielding, the back of the tweeter is sealed anyway, but I am not an expert at all in this area.
4 inches may be too close to use unshielded version. In addition, as far as HT gurus tell us, tweeter in front channels should be the same as the one in the center channel.
I have build 2 HT systems, with different tweeters and on the contrary to this believe, had no problems at all.
What would the limitations be in choosing a tweeter if the 2 woofers in the box have an SPL of 87 each? I know it's best to stay within 3db but is that a must?
I'm just trying to look at my options on choosing which tweeters would be available as far as specification limititions. Also, based on the Zetag specs, is there a maximum x-over frequency you would look at as far as these woofers go? Again, being a two way system, should I be looking at cetrain tweeters that can be crossed over at lower frequencies?
I'm just trying to look at my options on choosing which tweeters would be available as far as specification limititions. Also, based on the Zetag specs, is there a maximum x-over frequency you would look at as far as these woofers go? Again, being a two way system, should I be looking at cetrain tweeters that can be crossed over at lower frequencies?
The baffle step is theoretically 6dB and most compensate 3 to 6dB. Since the factory measurements are done on a large baffle it is the bass that drops and the upper mids stay as measured. You may need to lower the top end by this amount.
Using two drivers increases output by: from 3 to a theoretical 6dB.
I feel it would be most accurate to simulate all this as the measured responses (even the factory ones) don't always correlate to the published sensitivity. Furthermore, to a degree it may be design dependent. For example, the decision to go full D'Appolito style versus straight Linkwitz-Riley or 2.5 way, will produce different upper mid levels.
Using two drivers increases output by: from 3 to a theoretical 6dB.
I feel it would be most accurate to simulate all this as the measured responses (even the factory ones) don't always correlate to the published sensitivity. Furthermore, to a degree it may be design dependent. For example, the decision to go full D'Appolito style versus straight Linkwitz-Riley or 2.5 way, will produce different upper mid levels.
I found a good deal on a set of the Seas 27TDFC tweets and bought them. Not only did R-Carpenter recommend them but there is much love on the net for them from DIYers. I thing they will be good for me in that they are noted to be more detailed, which I like, but a fabric dome for more smooth response compared to my current titanium dome focals which are somewhat harsh at times.
Hopefully, these will be a good match for the Zetags.
Hopefully, these will be a good match for the Zetags.
The more I read about the Seas 27TDFC the more I like it. It was on my list of drivers to consider along with some Vifa and Morel models cost wise, but R-Carpenters recommendation made me take another look. Thanks to all who had information for me especially R-Carpenter. Now with a crossover makeover I am looking forward to what these drivers are going to sound like when completed.
Thanks again to all.
Thanks again to all.
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