Mid dome tests
I tried some things today, and I will start with the mid.
I played around with stuffing while watching the impedance curve, and not much happened unless I pressed the piece of foam from the mid enclosure to the felt on the back of the mid dome.
Next I wanted to try an extra magnet, but not much happened, and the magnet did not get a good 'connection' because of the felt, so i pulled off the felt, and then stuff started to happen! Now there was two resonance peaks in the impedance instead of the one damped peak before. The resulting peaks can be seen in the FR-graph.
So, the real factor seems to be the felt on the back of the dome, acting as a aperiodic vent. This dome does not seem good to use below 1k..
So, back went the felt, and I gave up on getting more low end extension from the mid..
More about XO test to come in next post.
I tried some things today, and I will start with the mid.
I played around with stuffing while watching the impedance curve, and not much happened unless I pressed the piece of foam from the mid enclosure to the felt on the back of the mid dome.
Next I wanted to try an extra magnet, but not much happened, and the magnet did not get a good 'connection' because of the felt, so i pulled off the felt, and then stuff started to happen! Now there was two resonance peaks in the impedance instead of the one damped peak before. The resulting peaks can be seen in the FR-graph.
So, the real factor seems to be the felt on the back of the dome, acting as a aperiodic vent. This dome does not seem good to use below 1k..
So, back went the felt, and I gave up on getting more low end extension from the mid..
More about XO test to come in next post.
Attachments
I modified the XO according to the Mod1 I posted before. However, I had to make some changes based on the components I found, so I'm attaching a *As Built' dxo.
There was a small bump in the woofer/mid XO, so put tried a smaller series cap for the mid to even that out. This was not seen in the sim. I might 'tune' this value still, but ran out of time for today.
I did one graph with a normal FR, and two mic positions with the mid inverted. It was pretty equal to the Mod1 sim I posted before.
So, it seems the measurement is not on my memory stick.. all I have are some pretty useless measurements of woofer with old vs Mod1 XO, and woofer and tweeter with normal vs inverted polarity.. So, that's what I'm posting for the moment.
Suggestions on some more cheap tricks are welcome! 🙂
There was a small bump in the woofer/mid XO, so put tried a smaller series cap for the mid to even that out. This was not seen in the sim. I might 'tune' this value still, but ran out of time for today.
I did one graph with a normal FR, and two mic positions with the mid inverted. It was pretty equal to the Mod1 sim I posted before.
So, it seems the measurement is not on my memory stick.. all I have are some pretty useless measurements of woofer with old vs Mod1 XO, and woofer and tweeter with normal vs inverted polarity.. So, that's what I'm posting for the moment.
Suggestions on some more cheap tricks are welcome! 🙂
Attachments
One thing came to mind regarding the mid resonances.. anybody with Ideas about where the two come from? Suspension is one for sure, but the other?
I have seen the same on tweeters with chambers, but here is no real chamber, it's more or less open back when the the felt was removed..
Any way to make the suspension softer without destroying the driver?
I have seen the same on tweeters with chambers, but here is no real chamber, it's more or less open back when the the felt was removed..
Any way to make the suspension softer without destroying the driver?
Well.. I listened to the modified speaker today, and I was not pleased. 'Edgy' midrange, and a bit sharp treble too.. Listened to the drivers one by one, and worst was the mid.
I could not help investigating the midrange a bit more, but there is not really much I can come up with. Seems like a weak motor with a light dome, very sensitive to everything around it, like cavities behind the dome and around the voice coil. Felt takes care of damping it, but somehow it seems like a bad patch job.
I remember building some speakers with the same mid domes in my youth, and I never liked those either.
I'm getting a little bit tired of these now.. had hopes of achieving something better sounding, maybe it's a small improvement with the modified XO, but still sound like s**t to me, even if they measure ok.
In desperation I even tried this (pic).. straight bolt on from some infinity speakers.
I could not help investigating the midrange a bit more, but there is not really much I can come up with. Seems like a weak motor with a light dome, very sensitive to everything around it, like cavities behind the dome and around the voice coil. Felt takes care of damping it, but somehow it seems like a bad patch job.
I remember building some speakers with the same mid domes in my youth, and I never liked those either.
I'm getting a little bit tired of these now.. had hopes of achieving something better sounding, maybe it's a small improvement with the modified XO, but still sound like s**t to me, even if they measure ok.
In desperation I even tried this (pic).. straight bolt on from some infinity speakers.
Attachments
Other mid alternatives I could use for this from leftovers are some Peerless TC9's (cheap but pretty good) and a pair Dynaudio D52 domes, some Vifa 5,25 poly mids..
Or just start from scratch and make a new baffle with other woofers, mids and tweeters.
Or I could do noting at all, and just be lazy and listen to music from speakers I like! 😉
Votes?
Or just start from scratch and make a new baffle with other woofers, mids and tweeters.
Or I could do noting at all, and just be lazy and listen to music from speakers I like! 😉
Votes?
I have yet to hear a set of Dali that didn't make me want to run away, but with that being said, it could still be a fun project. 🙂
Haha 🙂
I have not heard so many dali's, but in general I would agree.
I did active XO on a pair of Dali 810(replaced tweeters), and they sounded pretty good. I still have them in the garage thinking what to do with them. I re-used the P17 drivers from those to build front speakers for the TV. Nice sounding drivers, and easy to XO. The rest of them are also pretty good Vifa drivers, could make a good base for a project. Troels made a crossover for the 800's.
Been thinking of trying a wide baffle like Troels PMS using those drivers (left).. too many ideas for projects..
I have not heard so many dali's, but in general I would agree.
I did active XO on a pair of Dali 810(replaced tweeters), and they sounded pretty good. I still have them in the garage thinking what to do with them. I re-used the P17 drivers from those to build front speakers for the TV. Nice sounding drivers, and easy to XO. The rest of them are also pretty good Vifa drivers, could make a good base for a project. Troels made a crossover for the 800's.
Been thinking of trying a wide baffle like Troels PMS using those drivers (left).. too many ideas for projects..
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Nice project! 🙂 But not really low budget..
I have done active on Dali 810's (and others) with good results, but with separate amps and EQ APO in PC.
I want to stay passive because of the simplicity. I might give the speakers away to friends etc, so it should stay 'basic' and cheap but sound decent..
Waiting for the woofer foam surrounds to arrive so I can replace those. Have not decided on the mids, but leaning towards the Dynaudio mid domes. That would kind of 'stay true' to the original concept in some way.
BTW, how did you treat the wood veneer?
I have done active on Dali 810's (and others) with good results, but with separate amps and EQ APO in PC.
I want to stay passive because of the simplicity. I might give the speakers away to friends etc, so it should stay 'basic' and cheap but sound decent..
Waiting for the woofer foam surrounds to arrive so I can replace those. Have not decided on the mids, but leaning towards the Dynaudio mid domes. That would kind of 'stay true' to the original concept in some way.
BTW, how did you treat the wood veneer?
I know - it cost a bit. I actually have a set of coolbacks for sale.... but again - not really for low budget 😀
These are not my speakers - but I can ask him 🙂
These are not my speakers - but I can ask him 🙂
I have tried (measured and simulated) a number of mids now. The Dynaudio dome was too low efficiency, and so was the Peerless TC9. Vifa M13 from the Dali 810's was good, but requires baffle work, and acoustic offset to the tweeter is an issue. It's also a bit 'too good' for this speaker, and I had other plans for it.. Using that I should remake the baffle, time-align with tweeter, and preferably time-align the woofer too even if it looks ugly.
Doing so much work I should really put in a better tweeter too, it's not great. But, then the woofer is most likely not up to standard..
So, now I feel like giving up. Foam surrounds arrived today, so maybe I should do some 'therapy work' and replace those, and see if I get inspiration to do something with these boxes..
Right now I'm tired of them.
Doing so much work I should really put in a better tweeter too, it's not great. But, then the woofer is most likely not up to standard..
So, now I feel like giving up. Foam surrounds arrived today, so maybe I should do some 'therapy work' and replace those, and see if I get inspiration to do something with these boxes..
Right now I'm tired of them.
Before giving up, I recommend going the VituixCAD route. You won't have to bother with acoustic offsets (though you can still do it that way) and you will have an instant view of what your speaker is doing off-axis.
Here is a crossover that I had designed in SoundEasy (please disregard tweeter dip around 8kHz; I changed to a better tweeter afterwards). I used the same method as you have employed here (minimum phase response + relative acoustic offsets), represented here in VituixCAD. This is a similar project to yours; objective was to improve the existing crossover, which was indeed achieved with this crossover. Note good phase alignment at upper crossover point (3kHz) and satisfactory alignment at lower crossover (500Hz). The heat map shows the speaker's overall horizontal response from -90deg to +90deg; measurements done at 10 deg intervals. I achieved this by tuning the filter to match target LR4 filters, with Zmin constraint of 4 ohms.
Here is a further development of that filter, done in VituixCAD, accepting slight mis-tuning of target crossover frequencies (~400Hz, ~2500Hz) in order to achieve flatter on-axis and smoother off-axis response. Zmin dipped to 3.8Ohms at 100Hz. This time the objective was not to match idealised crossover topology & phase, but overall smoother on-axis, off-axis response.
I am quite chuffed at having discovered this tool. It really has changed how I will do my crossover designs going forward.
Here is a crossover that I had designed in SoundEasy (please disregard tweeter dip around 8kHz; I changed to a better tweeter afterwards). I used the same method as you have employed here (minimum phase response + relative acoustic offsets), represented here in VituixCAD. This is a similar project to yours; objective was to improve the existing crossover, which was indeed achieved with this crossover. Note good phase alignment at upper crossover point (3kHz) and satisfactory alignment at lower crossover (500Hz). The heat map shows the speaker's overall horizontal response from -90deg to +90deg; measurements done at 10 deg intervals. I achieved this by tuning the filter to match target LR4 filters, with Zmin constraint of 4 ohms.
Here is a further development of that filter, done in VituixCAD, accepting slight mis-tuning of target crossover frequencies (~400Hz, ~2500Hz) in order to achieve flatter on-axis and smoother off-axis response. Zmin dipped to 3.8Ohms at 100Hz. This time the objective was not to match idealised crossover topology & phase, but overall smoother on-axis, off-axis response.
I am quite chuffed at having discovered this tool. It really has changed how I will do my crossover designs going forward.
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Thank you for the encouragement! 🙂
However, I think the XO is not the problem, but the drivers. Especially the mid sounds bad. I guess the XO I made is a small improvement, but I'm not happy with the result because of the sound from the mid.
This is why I was thinking about replacing the mid, and tweeter, and time-align them, to make something better sounding, and easier to design a good XO.
Anyway, on top of this, I just found out the sourrounds for the woofers I received don't fit..(not angled to the cone)and I already removed the surround on one of them. Things have gone from bad to worse.
However, I think the XO is not the problem, but the drivers. Especially the mid sounds bad. I guess the XO I made is a small improvement, but I'm not happy with the result because of the sound from the mid.
This is why I was thinking about replacing the mid, and tweeter, and time-align them, to make something better sounding, and easier to design a good XO.
Anyway, on top of this, I just found out the sourrounds for the woofers I received don't fit..(not angled to the cone)and I already removed the surround on one of them. Things have gone from bad to worse.
hi Rallyfinnen !! This thread is a blessing from above. I have bought DALI 7 few days ago. I must admit with my SE lamp they sing... And the strongest part is the midrange. It is very interesting that you find midrange bad. I think that this is the best part of the speaker with nice plywood enclosure.
I wanted to ask. My left tweeter sounds dull compared to right. I measured them both at about 7 Ohm. They are VIFA D19TD-03 with double magnet. There is no pdf or anything about these ones. There is a pdf from VIFA for 05. The new ones Peerless by Tymphany D19TD-05 - they use ferrofluid. Mine was super dry. Idk if ferrofluid is gone but the magnetic cap was super clean.
The new ones from Tymphany measure at 6.2-6.3 Ohms.
Could you please measure the coil on the old and the new one??
I don't know if I should buy new ones. The DC resistance is a bit off from datasheet. (35years apart)
It would help a lot. Thanks!!
Ps. I didn't make any measurements with a reason. Wanted to listen before any numbers. And I love them. You can sit and listen all day long. I just sit and listen.
I'll get my UMIK-1 soon for REW.
Do you have a photo of original XO? I did wonder if 7A has the same XO or not. I know that the tweeter is metal dome from Seas.
I wanted to ask. My left tweeter sounds dull compared to right. I measured them both at about 7 Ohm. They are VIFA D19TD-03 with double magnet. There is no pdf or anything about these ones. There is a pdf from VIFA for 05. The new ones Peerless by Tymphany D19TD-05 - they use ferrofluid. Mine was super dry. Idk if ferrofluid is gone but the magnetic cap was super clean.
The new ones from Tymphany measure at 6.2-6.3 Ohms.
Could you please measure the coil on the old and the new one??
I don't know if I should buy new ones. The DC resistance is a bit off from datasheet. (35years apart)
It would help a lot. Thanks!!
Ps. I didn't make any measurements with a reason. Wanted to listen before any numbers. And I love them. You can sit and listen all day long. I just sit and listen.
I'll get my UMIK-1 soon for REW.
Do you have a photo of original XO? I did wonder if 7A has the same XO or not. I know that the tweeter is metal dome from Seas.
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Lucky for you you like them 🙂 For me they failed the 'garage listening' and never even made it in to the living room..
There was no ferro-fluid in my tweeters either, but mine are plastic dome, not aluminium. I'm pretty sure there was never any ferro fluid in these, it would be visible, but mine were just as clean as yours. I just added FF just to avoid burning the tweeters again, but 'some say' it's not good for the micro details. I think you should measure your tweeters response. You can also check for rubbing by feeding a (weak) LF signal of maybe 200Hz and putting your ear to the tweeter, should sound clean. Check the windings on the voice coil closely too.
If resistance is normal, and tweeters look good inside, I think chances are that they are ok. Maybe tweeters are ok, but there is some problem in the wiring or XO? Have you tried switching the tweeters between speakers to see if the problem follows the tweeter?
I'm not sure if our tweeters are comparable if they don't have the same dome. I think most of the D19's sold were plastic domes?
I did have a picture of the std XO in my phone.
There was no ferro-fluid in my tweeters either, but mine are plastic dome, not aluminium. I'm pretty sure there was never any ferro fluid in these, it would be visible, but mine were just as clean as yours. I just added FF just to avoid burning the tweeters again, but 'some say' it's not good for the micro details. I think you should measure your tweeters response. You can also check for rubbing by feeding a (weak) LF signal of maybe 200Hz and putting your ear to the tweeter, should sound clean. Check the windings on the voice coil closely too.
If resistance is normal, and tweeters look good inside, I think chances are that they are ok. Maybe tweeters are ok, but there is some problem in the wiring or XO? Have you tried switching the tweeters between speakers to see if the problem follows the tweeter?
I'm not sure if our tweeters are comparable if they don't have the same dome. I think most of the D19's sold were plastic domes?
I did have a picture of the std XO in my phone.
Attachments
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BTW, you can add some felt to the pole piece of the tweeter. I just used some of those round felt pads they sell to use for furniture legs etc, with adhesive on one side, just stick them on. It removed a deep null in the top octave on my tweeters.
Thanks. I have indeed switched tweeters and the problem follows the tweeter.
It looks good. Maybe there is not enough pressure from the magnet on the front of the tweeter? I really don't know.
If there was no fluid I will not add any. They lasted 35y and look like new.
I will try to add felt. D19TD were plastic domes. Seas ones are made of fabric.
They have nicer curve but idk.
First time when i hooked them to my living room space (not my "mancave" listening area) I was really disappointed. I was about to call the guy and give them back.
But something told me that I should give them a chance (I have super good experience with dome midrange before).
Boy they are singing now. One of the best I have ever heard. Idk why the difference is so huge (living room transistor 55m2) (man cave 20m2 tube)
This are one of the speakers I fell in love with.
What really bothers me is that the new d19td are ferrofluid type with single magnet. The question is - should I go for D19TD05 with 88db? Or try this Seas nonferro 90db ones. I'm sure that lack of FF and double magnet must have had an impact on them tweeters.
I understand that you don't have them anymore.
What do you think about tweeters replacement?
It looks good. Maybe there is not enough pressure from the magnet on the front of the tweeter? I really don't know.
If there was no fluid I will not add any. They lasted 35y and look like new.
I will try to add felt. D19TD were plastic domes. Seas ones are made of fabric.
They have nicer curve but idk.
First time when i hooked them to my living room space (not my "mancave" listening area) I was really disappointed. I was about to call the guy and give them back.
But something told me that I should give them a chance (I have super good experience with dome midrange before).
Boy they are singing now. One of the best I have ever heard. Idk why the difference is so huge (living room transistor 55m2) (man cave 20m2 tube)
This are one of the speakers I fell in love with.
What really bothers me is that the new d19td are ferrofluid type with single magnet. The question is - should I go for D19TD05 with 88db? Or try this Seas nonferro 90db ones. I'm sure that lack of FF and double magnet must have had an impact on them tweeters.
I understand that you don't have them anymore.
What do you think about tweeters replacement?
If you suspect leakage on the back, maybe you can try some 'goo' to seal between face-plate and magnet first.
You could do like me, and re-use the magnets, and just take the face-plate from the new tweeters. You can remove the FF from the coil of the new face-plate.
There are connectors to the rear terminal, so you don't have to remove it when you take out the XO (behind woofer).
You could do like me, and re-use the magnets, and just take the face-plate from the new tweeters. You can remove the FF from the coil of the new face-plate.
There are connectors to the rear terminal, so you don't have to remove it when you take out the XO (behind woofer).