I am wondering about the results - or lack thereof - when I try to measure a Linaeum ET-8 tweeter. I get a value for the R(e) of 7.33 ohms and for L(e) of 0.02776mH only; and I get a nearly flat red trace (phase?) and a very flat blue trace (impedance?) that rises a bit starting at 5kHz.
Due to the design of this tweeter, what should I use for the piston diameter?
It does not allow me to go on to use Measure V(as).
To design a 2nd order (12dB/octave) crossover for this tweeter - do I need to know more data, than the R(e) and L(e)?
Due to the design of this tweeter, what should I use for the piston diameter?
It does not allow me to go on to use Measure V(as).
To design a 2nd order (12dB/octave) crossover for this tweeter - do I need to know more data, than the R(e) and L(e)?
Impedance / Phase Blip?
I think my DATS V3 is at least functioning - I just measured the two Dayton Audio RS225P-8A woofers I am planning on using, and everything works as expected. So, maybe the Linaeum tweeters are not workable with the DATS V3?
On the woofers - on the attached screen capture, what is the significance of the strong blip at about 650Hz?
I think my DATS V3 is at least functioning - I just measured the two Dayton Audio RS225P-8A woofers I am planning on using, and everything works as expected. So, maybe the Linaeum tweeters are not workable with the DATS V3?
On the woofers - on the attached screen capture, what is the significance of the strong blip at about 650Hz?
Attachments
> blip at about 650Hz
The rear spider is enormous and probably resonates there. It is well coupled to the voice coil (thus to DATS) but poorly coupled to the room (the cone is in the way).
The Linaeum is not a voice-coil, not a good "motor", and should show a benign impedance. It is not an open-back driver so "Vas" is built-in, and probably meaningless except to the Linaeum designer. The equivalent "piston diameter" is very vague because the Linaeum does not work like a simple piston.
If you have to ask (you don't have deep experience matching driver curves), then just design the high-pass for the recommended frequency and nominal impedance.
The rear spider is enormous and probably resonates there. It is well coupled to the voice coil (thus to DATS) but poorly coupled to the room (the cone is in the way).
The Linaeum is not a voice-coil, not a good "motor", and should show a benign impedance. It is not an open-back driver so "Vas" is built-in, and probably meaningless except to the Linaeum designer. The equivalent "piston diameter" is very vague because the Linaeum does not work like a simple piston.
If you have to ask (you don't have deep experience matching driver curves), then just design the high-pass for the recommended frequency and nominal impedance.
Thank you for the responses. The spider is probably the issue - it is not vented on this otherwise wonderful driver.
Here are the four sets of measurements on the four Linaeum ET-6A tweeters:
They are dipole and they are open - there is space above and below the curved leaves. The phase is nearly perfect as far as I can see, and the impedance traces are grouped, so I am "matching" the magenta and green, and the blue and the yellow.
I am planning on crossing these at 1100Hz for the tweeters and 1000Hz for the woofers, with 12dB/octave Linkwitz Riley filters. I have been listening and experimenting with a miniDSP 2x4 HD. They don't need PEQ on the drivers. The cabinets I built previously use the 4 ohm version of the woofer, so I am lowering the woofer level about 2dB. In the new cabinets that I will be building, and using the 8 ohm woofers, I will probably have to lower the tweeter level ~2-3dB, since the 4 ohm woofers are about 4dB louder at a given power level vs the 8 ohm.
Here are the four sets of measurements on the four Linaeum ET-6A tweeters:
They are dipole and they are open - there is space above and below the curved leaves. The phase is nearly perfect as far as I can see, and the impedance traces are grouped, so I am "matching" the magenta and green, and the blue and the yellow.
I am planning on crossing these at 1100Hz for the tweeters and 1000Hz for the woofers, with 12dB/octave Linkwitz Riley filters. I have been listening and experimenting with a miniDSP 2x4 HD. They don't need PEQ on the drivers. The cabinets I built previously use the 4 ohm version of the woofer, so I am lowering the woofer level about 2dB. In the new cabinets that I will be building, and using the 8 ohm woofers, I will probably have to lower the tweeter level ~2-3dB, since the 4 ohm woofers are about 4dB louder at a given power level vs the 8 ohm.
