You mean they appear happy......what they say and what you get are two very distinct things as I found out
Right after a lot of depressing posts about the passive crossovers, I thought I would try to uplift this thread with some quick and dirty measurements taken with my UMIK-1 and REW using three power amps and an analogue crossover.
I experimented with various crossover points and have settled at approx 480hz and 4000hz.
Here are the slopes, the combined response, distortion measurements and a plot of the phase. Not bad for a very quick play this morning!
Obviously these have been taken in a fairly terrible location as pictured earlier in my study and are therefore not the best, taken at 1m tweeter height.
I experimented with various crossover points and have settled at approx 480hz and 4000hz.
Here are the slopes, the combined response, distortion measurements and a plot of the phase. Not bad for a very quick play this morning!
Obviously these have been taken in a fairly terrible location as pictured earlier in my study and are therefore not the best, taken at 1m tweeter height.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Sorry about the mis-description of the active crossover.
The project was slightly more advanced than I remembered.
There is indeed a PSU with 0-15 + 0-15V 50VA transformer into substantial high speed bridge and Philips 22000uF caps.
There are two LM317/LM337 boards set to approx +/- 15V I seem to recall.
The 2 x P90 Linkwitz cossovers are as yet un-mounted. The Euro Mains Plug has been fitted.
Basically you get what you see in the photo plus the lid for the chassis.
The Op-Amps are OPA2604s. Quality components were used throughout the build and all closely matched.
The project was slightly more advanced than I remembered.
There is indeed a PSU with 0-15 + 0-15V 50VA transformer into substantial high speed bridge and Philips 22000uF caps.
There are two LM317/LM337 boards set to approx +/- 15V I seem to recall.
The 2 x P90 Linkwitz cossovers are as yet un-mounted. The Euro Mains Plug has been fitted.
Basically you get what you see in the photo plus the lid for the chassis.
The Op-Amps are OPA2604s. Quality components were used throughout the build and all closely matched.
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It will be good to see how things develop. Are these active analogue crossovers using op-amps or something else? Is it what you intend to use longer term? Do you intend to use the crossover for more than the crossover slopes?
Basic analogue variable pro crossover - dbx.
I find it very useful for modelling different crossover points and taking measurements whilst protecting the drivers in their passbands.
I believe the quested and ATC active versions that use the same drivers as these, use 4th order electrical slopes, and I was pleased with the measured phase and coherency of the set-up as is.
I was planning on going fully digital - PC source - digital crossover, or PC based crossover - but they sound really excellent now, so I will give it a few weeks to see how things go.
I find it very useful for modelling different crossover points and taking measurements whilst protecting the drivers in their passbands.
I believe the quested and ATC active versions that use the same drivers as these, use 4th order electrical slopes, and I was pleased with the measured phase and coherency of the set-up as is.
I was planning on going fully digital - PC source - digital crossover, or PC based crossover - but they sound really excellent now, so I will give it a few weeks to see how things go.
I'm confused now, AFAIK ATC don't use any of the drivers you have do they? Don't you have Volt Radial, Volt Dome and a Scanspeak tweeter? Or haven't I been paying attention? I agree about Prestige sounding excellent with pro analogue active crossovers. I think the precision of fixed resistors for the crossover points would be better though.
Yes, that makes sense and AFAIK you are correct. I think you can add PMC to the list too, they use very slightly modified versions of the Radial with their own version of the ATC dome but with a lower spec tweeter (again modified slightly). I always wanted to find out how PMC do their ATL cabinets (for such as the MB2), the bass from them is amazing, better than these reflex boxes. Might be something for the future. WA do have a design for this using Prestige drivers but I have no idea what they sound like.
My question was prompted by the smooth but elevated and less than flat midrange response seeming to need a bit of work. With DSP this should be straightforward. Given the smoothness it should also be not too difficult with passive components. I think you can also see a hint of the influence of the baffle which someone referred to earlier but it doesn't look large even with the blown up scale.
It will be interesting to compare with the fixed passive crossovers.
A little bit of digging around on the WA website shows this: There is only one Prestige crossover offered and "The response crossover points are set at 400Hz and 3800Hz " in addition the spec for the Volt VM752 gives frequency response as "Frequency range: 500Hz - 4000Hz" so there is at least a 100Hz gap. Spookily the prices for the K50 and K100 kits are exactly the same as for the two Prestige models. It makes me wonder if they are supplying the same crossover for all four models and possibly have decided to standardize on the ATC clone crossover.
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A friend of mine told me that ATC-150 mid would loose sensibility over time as it collects dust on the heavy coating.
He spoke from experience from a well known studio. A gap will appear.
However, this is the crossover I bought from WA: (#3), backward drawing in XSim as I did not receive any schematics:
W18EX001/T29MF001 ?MAGNUM" i MTM-WW
He spoke from experience from a well known studio. A gap will appear.
However, this is the crossover I bought from WA: (#3), backward drawing in XSim as I did not receive any schematics:
W18EX001/T29MF001 ?MAGNUM" i MTM-WW
The price at both Falcon and Wilmslow of the Volt VM752 which Bushmeister is listening to in his speakers is £518.70 each which is over £1000 for a pair.
The ATC and Volt are both 3" soft domes with large magnets but there are significant differences in the details. The ATC also comes in a number of variations some of which are available to DIYers and some of which are not.
The Volt is roughly equivalent to the (non-avalable) S version of the ATC.
At least in terms of sensitivity and weight (Volt and S weigh 9kg, two more than the non-S ATC).
I think as a replacement part the S costs about the same as the Volt as well.
But information is scant and I'm not sure about its reliability.
At least in terms of sensitivity and weight (Volt and S weigh 9kg, two more than the non-S ATC).
I think as a replacement part the S costs about the same as the Volt as well.
But information is scant and I'm not sure about its reliability.
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Hi I have both the standard and S versions of the ATC mid. Both sound much the same but the S version is 3dB more sensitive. The Volt is really a replacement for the SM75-150S (super) although is only suitable for 500Hz crossover. ATC no longer supply the s version for DIY.
I have used the atc's in many designs over the past 15 years. They are best crossed over at 380 and 3500. (As atc do in their own speakers).
A passive crossover implementation is not straight forward at 380Hz crossover point. To do this you need to equalise 320Hz Fs using a series LRC and also equalise a peak at around 1Khz using a second LRC. These are the values I use for the 8ohm version of the ATC.
1. 100uF + 2.5mH + 9ohms (For the 320Hz Fs)
2. 6uF + 5mH + 9 ohms (For the 1kHz peak)
The 9 ohms values include the R for the inductors - so adjust the resistor to allow for the series R of the inductors actually used. This value can be also be adjusted to fine tune for specific baffle designs.
The circuits should also work for the 16ohm ATC mid but increase R to 16ohms. You need to measure to get the ideal values.
If you add the FS LCR then you will need to adjust the LC values of the high pass filter used on the WA design because the overall impedance at the crossover point has been lowered by the FS LCR. I will post the circuit I use for the 8ohms version of the standard and S ATC mid.
Hope this helps (WA design definitely not 380Hz crossover)
I have used the atc's in many designs over the past 15 years. They are best crossed over at 380 and 3500. (As atc do in their own speakers).
A passive crossover implementation is not straight forward at 380Hz crossover point. To do this you need to equalise 320Hz Fs using a series LRC and also equalise a peak at around 1Khz using a second LRC. These are the values I use for the 8ohm version of the ATC.
1. 100uF + 2.5mH + 9ohms (For the 320Hz Fs)
2. 6uF + 5mH + 9 ohms (For the 1kHz peak)
The 9 ohms values include the R for the inductors - so adjust the resistor to allow for the series R of the inductors actually used. This value can be also be adjusted to fine tune for specific baffle designs.
The circuits should also work for the 16ohm ATC mid but increase R to 16ohms. You need to measure to get the ideal values.
If you add the FS LCR then you will need to adjust the LC values of the high pass filter used on the WA design because the overall impedance at the crossover point has been lowered by the FS LCR. I will post the circuit I use for the 8ohms version of the standard and S ATC mid.
Hope this helps (WA design definitely not 380Hz crossover)
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