5th element said:
Hey, it would certainly minimise IM distortion!
Saurav
Seriously, go with what sounds good to you, and if it measures well as well, then thats even better. You can't just look at charts to appreciate how a driver will sound, and after all, until the graphs were posted, everyone was recommending them...
If you really want to try doping, ( though I like the drivers, and am not convinced they need it), then use I would use diluted PVA, applied in very thin misted coats with a spray bottle. That way you can apply a little at a time, let it dry well inbetween coats, and see what you think after each application.
Id say just go with what sounds good aswell. Just because a driver has a cone res in its passband doesnt make it sound rubbish, many poly cones are in breakup thru the entire high freq passband. After all many people like the PR170MO anyway so it cant be that bad!
However I would recommend trying a different tweeter that can crossover lower, ofcourse if you are happy with the sound then dont bother. The only designs I can think of that would satisfy the sensativity are the new scan models and the focal inverted tweets, if you dont wanna go horn that is.
However I would recommend trying a different tweeter that can crossover lower, ofcourse if you are happy with the sound then dont bother. The only designs I can think of that would satisfy the sensativity are the new scan models and the focal inverted tweets, if you dont wanna go horn that is.
And I thought I saw some Audax fabric/soft dome tweeters on Parts Express that were up in the 96dB range too. And there's the GR Research tweeter that says 96, but I can't find any information on it on any of the forums.
I also think I'll take your advice for now and stay away from doping. It makes more sense to get a different tweeter and cross over lower, than to try doping this driver. And AFAIK it's not known for longevity anyway.
Thanks for all the help guys.
I also think I'll take your advice for now and stay away from doping. It makes more sense to get a different tweeter and cross over lower, than to try doping this driver. And AFAIK it's not known for longevity anyway.
Thanks for all the help guys.
My first thoughts would be to start with an electrical filter around 3KHz which should bring the response down flat out to 3KHZ and the acoustic X-over would be around 4-5KHZ. Second thought would be to tilt the driver and listen to it off axis where the response is pretty flat and rolls off nicely. I think Variac had a similar setup on his open baffle where he could tilt the driver/baffle. I'll have to get the IMP analyzer out and run some tests.
BDP
BDP
You might look at the Aurum Cantus G2si ribbon with a 6 ohm
impedience 96db/watt sensitivity and a lowest recomended xover
of 2750 hz when using a 3rd order xover or higher. These are available in the USA from e-speakers at $99 each. And if you
are only using 4 or 5 watts you might be safe using a first order
at 3k or above.
impedience 96db/watt sensitivity and a lowest recomended xover
of 2750 hz when using a 3rd order xover or higher. These are available in the USA from e-speakers at $99 each. And if you
are only using 4 or 5 watts you might be safe using a first order
at 3k or above.
I have been doing some measurements with my IMP analyzer on the PR170M0 and AC G2 set up on an open baffle measuring 17 inches by 25 inches. The lower roll off of the midrange was about -3db at about 300Hz which is predicted. This is without the extra area of the bass box which will extend the response even lower although it will be crossed over to the bass at about 300 to 400 Hz. The baffle is adjustable for tilting the mid driver back to get some off axis measurements. I'll post some pictures later of the setup and if I can figure out how to post the IMP frequency response files I'll post some of those also.
I have put together about four different x-overs at various frequencies and slopes. All measured within a 3dB window. The frequencies varied from 3.8KHz to 5.7KHz. I tried a x-over at 2.7KHZ but didn't like the sound of that combination. I tried listening to the driver without a x-over on the mid range and didn't particularly like that either, so what I will comment on are the ones in between. First I would like to say that the AC G2 is very easy to x-over with its flat impedance and frequency response, they are pretty much text book. The sensitivity of the two drivers are almost perfect so not much attenuation is needed. Most of the x-overs I have put together have no attenuation on the tweeter.
So far I have liked two of the x-overs best. The 3.8KHz and 5.7KHz. The 3.8Khz is a 1st order on the mid, 2nd order on the G2 and the baffle tilted about 10 degrees. The mid has a zobel of 12uF in series with 8 ohm resistor. This resulted in an impedance of 7.75 ohms. L1 on the mid is .45mH. This helped bring down the peaks at 2 and 3KHz. The G2 C1 is 4uF and L2 is .3mH and drivers are in phase. The 5.7KHz is 2nd order on both drivers and in phase with the baffle again tilted 10 degrees. The mid range L1 is .33mH and 2.75 uF. The G2 C1 is 2.8uF and .275 mH.
These are all very preliminary and can easily change. I'm going to listen more and then do more measuring on the ones that I think have sounded the best. I would have thought that running the midrange out to 5.7KHz would cause more off axis sound problems but this driver sounds good. More time will tell.
It is really easy to put a x-over together in no time and it even can measure good but the sound might not be optimum.
More later
BDP
I have put together about four different x-overs at various frequencies and slopes. All measured within a 3dB window. The frequencies varied from 3.8KHz to 5.7KHz. I tried a x-over at 2.7KHZ but didn't like the sound of that combination. I tried listening to the driver without a x-over on the mid range and didn't particularly like that either, so what I will comment on are the ones in between. First I would like to say that the AC G2 is very easy to x-over with its flat impedance and frequency response, they are pretty much text book. The sensitivity of the two drivers are almost perfect so not much attenuation is needed. Most of the x-overs I have put together have no attenuation on the tweeter.
So far I have liked two of the x-overs best. The 3.8KHz and 5.7KHz. The 3.8Khz is a 1st order on the mid, 2nd order on the G2 and the baffle tilted about 10 degrees. The mid has a zobel of 12uF in series with 8 ohm resistor. This resulted in an impedance of 7.75 ohms. L1 on the mid is .45mH. This helped bring down the peaks at 2 and 3KHz. The G2 C1 is 4uF and L2 is .3mH and drivers are in phase. The 5.7KHz is 2nd order on both drivers and in phase with the baffle again tilted 10 degrees. The mid range L1 is .33mH and 2.75 uF. The G2 C1 is 2.8uF and .275 mH.
These are all very preliminary and can easily change. I'm going to listen more and then do more measuring on the ones that I think have sounded the best. I would have thought that running the midrange out to 5.7KHz would cause more off axis sound problems but this driver sounds good. More time will tell.
It is really easy to put a x-over together in no time and it even can measure good but the sound might not be optimum.
More later
BDP
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