I had a pair of these on the shelf for about 10 years with a crossover and Vifa D19 tweeters that were cannibalised somewhere along the line.
Wanting to re-instate and use up the spare parts bin, I re-measured and designed a new crossover. I ended up being a little aggressive on BSC according to the measurements, but it actually sounds balanced to my ear in my room (so far), so will leave as is. This could be an artefact of the final measure I did which wasn't in the same environment as the raw driver measurements. Crossover uses unsmoothed but gated responses, with quasi-nearfield woofer (nearfield + BSC merged with gated farfield). Final measure (green/red each speaker) is full in room sweep with 1/3rd octave smoothing.
The last curve is RED/GREEN = measured left/right speakers in room and ORANGE = simulation (based on individual driver measurements). Z offset (not in picture - set on driver tab) 36mm on woofer.
Wanting to re-instate and use up the spare parts bin, I re-measured and designed a new crossover. I ended up being a little aggressive on BSC according to the measurements, but it actually sounds balanced to my ear in my room (so far), so will leave as is. This could be an artefact of the final measure I did which wasn't in the same environment as the raw driver measurements. Crossover uses unsmoothed but gated responses, with quasi-nearfield woofer (nearfield + BSC merged with gated farfield). Final measure (green/red each speaker) is full in room sweep with 1/3rd octave smoothing.
The last curve is RED/GREEN = measured left/right speakers in room and ORANGE = simulation (based on individual driver measurements). Z offset (not in picture - set on driver tab) 36mm on woofer.
Nice work, @Dave Bullet!
I think that tweeter peak at 10kHz is what plastic domes like the popular old Vifa D19 do. Usually very bright at the top.
Whether the grille cloth helps, or whether that is better listened to off-axis is for your ears. I might experiment with a Zobel across the tweeter, after the very conventional tweeter filter..
About 7.5R (3W) and about 0.68uF can help IMO. You might try changing the second tweeter capacitor of 7.2uF to between 4,7uF and 10uF and see how the sim then looks too.
Best, Steve.
I think that tweeter peak at 10kHz is what plastic domes like the popular old Vifa D19 do. Usually very bright at the top.
Whether the grille cloth helps, or whether that is better listened to off-axis is for your ears. I might experiment with a Zobel across the tweeter, after the very conventional tweeter filter..
About 7.5R (3W) and about 0.68uF can help IMO. You might try changing the second tweeter capacitor of 7.2uF to between 4,7uF and 10uF and see how the sim then looks too.
Best, Steve.
Thanks Steve. I had this series notch to tame the top end (at the cost of an impedance dip), but no appropriate spare parts. The hot high end seems to work though in room. must be my aging ears 🙂
That speaker is designed to run bass at top! No wonder I couldn't read the logo.... maybe it's different in Australia? 🤣
I looked the tweeter up. I get the feeling the Vifa TD19-05 is plastic and the Vifa TD19-05-08 is fabric, but it's confusing. Maybe it's plasticised fabric?
PDF here: https://willys-hifi.com/products/peerless-d19td05-08-tweeter
I wanted to know what its inductance and DCR is. 0.02mH and 6.3R according to the spec sheet, but I think about 0.07mH is probably right.
Its impedance certainly rises faster than this similar SEAS 19TAFD-G which is 0.05mH as SEAS measure it. I know that metal SEAS tweeter well. It's rather good.
https://www.seas.no/index.php?optio...dg&catid=45:seas-prestige-tweeters&Itemid=462
That would make a sensible RC Zobel around 7.5R seriesed with about 1uF. A cheap MKT or pricier MKP type will do nicely. You will find impedance improves too.
It is ferrofluid too, so that can dry out with age and lose loudness. Hard stuff to find, ferrofluid. Easy to replace it if you carefully unclip the tweeter magnet vertically so as not to damage the voicecoil.
http://www.bluearan.co.uk/index.php?id=SONFF05
Anyway, it's up to you how much you fiddle around here! I enjoy twiddling these things. 🙂
I looked the tweeter up. I get the feeling the Vifa TD19-05 is plastic and the Vifa TD19-05-08 is fabric, but it's confusing. Maybe it's plasticised fabric?
PDF here: https://willys-hifi.com/products/peerless-d19td05-08-tweeter
I wanted to know what its inductance and DCR is. 0.02mH and 6.3R according to the spec sheet, but I think about 0.07mH is probably right.
Its impedance certainly rises faster than this similar SEAS 19TAFD-G which is 0.05mH as SEAS measure it. I know that metal SEAS tweeter well. It's rather good.
https://www.seas.no/index.php?optio...dg&catid=45:seas-prestige-tweeters&Itemid=462
That would make a sensible RC Zobel around 7.5R seriesed with about 1uF. A cheap MKT or pricier MKP type will do nicely. You will find impedance improves too.
It is ferrofluid too, so that can dry out with age and lose loudness. Hard stuff to find, ferrofluid. Easy to replace it if you carefully unclip the tweeter magnet vertically so as not to damage the voicecoil.
http://www.bluearan.co.uk/index.php?id=SONFF05
Anyway, it's up to you how much you fiddle around here! I enjoy twiddling these things. 🙂
Thanks - your suggested Zobel before tweeter terminals has no effect on frequency response. For taming the top end, the series circuit I posted would work well I think (if I had the parts).
I must admit, I didn't look at the sub part numbers of the D19 to compare old and new. The crossover is custom to the measured drivers, so that's all good.
I realise the originals are MT orientation. I'm positioning them however TM for my listening position and designed on the tweeter axis, hence the upside down logo. You're right about southern hemisphere though 🙂 We do things upside down so they make sense to you right side up people 😀
Thanks for the tip on the ferrofluid. The raw impedance sweeps for both D19 are quite similar and very close to factory, so I'm taking it that the ferrofluid is still ok.
I must admit, I didn't look at the sub part numbers of the D19 to compare old and new. The crossover is custom to the measured drivers, so that's all good.
I realise the originals are MT orientation. I'm positioning them however TM for my listening position and designed on the tweeter axis, hence the upside down logo. You're right about southern hemisphere though 🙂 We do things upside down so they make sense to you right side up people 😀
Thanks for the tip on the ferrofluid. The raw impedance sweeps for both D19 are quite similar and very close to factory, so I'm taking it that the ferrofluid is still ok.
I don't think the Zobel idea was a bad one. It does rely on an input resistor (Here 2.2R) to work.
I got -2dB with 7.5R and 1uF, though to my ears it always sounds MUCH quieter at the top. 7.5R and 2.2uF would do even more around -3dB, which is half power. Old trick to tame harsh metal tweeters!
Anyway, enjoyed getting the old Boxsim out of retirement. Take care. 🙂
I got -2dB with 7.5R and 1uF, though to my ears it always sounds MUCH quieter at the top. 7.5R and 2.2uF would do even more around -3dB, which is half power. Old trick to tame harsh metal tweeters!
Anyway, enjoyed getting the old Boxsim out of retirement. Take care. 🙂
I have a pair of Mission 70's that I bought in the early 1980's. I think I can update the crossover (very primitive looking) to this crossover. However, I have never done this. From looking at the picture I think I can buy [most of] the parts on parts express. Not sure I understand exactly how to lay out the crossover though. Can you show me a picture of the actual crossover? What is best from above and any advice? Thanks in advance!