I retested on the hardwood floor. Results haven't changed. New theory- I might have fried the exciters. I have another set I can try but I don't have time now. Going forward I think I am just going to use the proximity testing method and probably start the sweep at 100Hz or so. That will keep the watts down and protect the exciters + amp. I will save the proximity testing for when I actually have these mounted. I have 2 new exciters I can swap in so I will test those later. I hope that is the issue. I really liked the original response I got....
Hi, everyone. I want to start by thanking you all for everything you give back to the community. Anyone heard about the Yamaha JA-6001? Big Styrofoam speakers from the 70's. Chasing the dml Holly Grail I got interested in this speakers and managed to get a smaller version of this ones. They sound amazing taking into consideration my equipment. If enough interst I might take them apart and post some detailed pictures of my witch I belive has the JA-3502 driver. I just ordered some exciters to try and make something similar to the Yamaha but with the dayton audio exciters. Oh the ja-6001 is big: 880 x 640 x 180 mm / 34.6 x 25.2 x 7.1 inch.
Sorry if I went off the tracks but I thought it was strange nobody brought this type of speakers into discussion.
Hope It works 🤔 and helps😁
Sorry if I went off the tracks but I thought it was strange nobody brought this type of speakers into discussion.
Hope It works 🤔 and helps😁
Attachments
Hello Toddincado,
To be sure to follow you : the left panel of the picture here below is what gives you satisfaction? So the plywood working around the exciter and then the EPS.
Would you remind the dimensions of your panel, its thickness? Just to add some information in an update of the history file I already posted.
Your solution to attached the exciter is interesting. Not so easy to keep it straight, with no effort from the cable neither effort on the voice coil.
About your listening feedback, I could make about the same comment : it is on the vocals we detect the defects while having a very good sound (probably not necessary the exact one but the one we like) on instruments. Is the panel coloration good for instruments not for the voice?
Christian
Christian.
On post 3162 in picture 3 is the frequency response of my canvas panel at 3ft .
the response falls off at 40hz the resonance is higher .
if you make the panel too tight it will start to make a sound of its own , could this be the coloration you are hearing ?
I seem to remember vocals sounding very good, and natural ?
The harshness of the small ply panel is very well controlled by the canvas and pva.
just a thought.
Steve.
On post 3162 in picture 3 is the frequency response of my canvas panel at 3ft .
the response falls off at 40hz the resonance is higher .
if you make the panel too tight it will start to make a sound of its own , could this be the coloration you are hearing ?
I seem to remember vocals sounding very good, and natural ?
The harshness of the small ply panel is very well controlled by the canvas and pva.
just a thought.
Steve.
aagas.
So when you whip the pva , it does not slowly turn back to liquid form before it dries ?
pva being water based ,I would have thought that confining it between two plates of aluminium would seal the water in ,at least for a long time ?
even with the wooden frame ?
When I used to use two aluminium plates glued together I had to use a spray adhesive mount , as pva would not dry.
The same happens when gluing two pieces of xps together .
Does the pva foam have to dry before applying the second plate ?
Steve.
So when you whip the pva , it does not slowly turn back to liquid form before it dries ?
pva being water based ,I would have thought that confining it between two plates of aluminium would seal the water in ,at least for a long time ?
even with the wooden frame ?
When I used to use two aluminium plates glued together I had to use a spray adhesive mount , as pva would not dry.
The same happens when gluing two pieces of xps together .
Does the pva foam have to dry before applying the second plate ?
Steve.
Hi,
Those speakers were already mentioned in this thread and also I think in the historic "NXT...rubbish?" audiocircle thread. Usually, Bertagni speakers are also mentioned in such discussions.
You can have a look here around p114 #2273 with a link to japanese pages about them.
As far I remember (memory...), I haven't seen clones of those speakers. Some design solutions are used : reduced thickness at the axis, non rectangular shape (few example, see Toddincabo just before), ribs but no so popular (perhaps difficult for most of us).
To know the membrane thickness or the suspension solution could help. The frequency response?
The funny side of your post is that by searching a little about the Yamaha, I found posts about topics I have in mind at the moment (room interaction, baffle...)
Christian
@aagas
Same questions from my side. ;-)
@spedge
With DML, I learnt to use watered PVA. If it can help : I made different gluing by applying first one or two layers of watered PVA (even more than 50% of water) on each part to glue. When dry, I glue the parts together with 100% PVA. I did that for wood (no primary layer for wood) on XPS, EPS on EPS. Also for the foam I used for the plywood panel suspension. It is a 17x17mm foam seal (from 3M for garage door). There is one adhesive on one side that I glued on the frame. Then 2 layers of watered PVA on the face to be in contact with the membrane. Wait one day between layers then apply the PVA glue and put under a little pressure the membrane wait for an other 24 hours. This remove the warping of the 3mm membrane. The last test I did was with pieces of foam rubber. a test in the idea to use it later as suspension. With just PVA, it didn't work. With a first layer on each piece and waiting for a long, very long, very very long time... the PVA dried. Not too bad (the foam rubber seems a bit porous).
For aluminum, hmm... what will happen?
I like the question about the whipped PVA. It is like snow-white with eggs (I like cooking!). A pinch of salt to help?
Christian
I will measure the thickness of the membrane as I suspect that might be key to some results but I can tell you what it is not brilliant in the upper frequencies. They do o have tweeters but not that effective, probably just old caps. I have to look in to it and post rsults but no calibrated mic available now. I agree on the shape but only for low frequencies as I have a mid bass with different shape. One panel fits all seams a bit hard to get without dsp. Thanks and looking forward to see what happens
Christian.
I looked back to page 114 and remembered that I nearly bought one of these ear speakers ,but managed to keep my fingers off the button 😁
the last thing I need is another panel.
anyway I noticed on page 115 I made some recordings from an MA download using some various old eps panels I had lying around.
these are live acoustic recordings in a church I believe , which comes across very well with eps.
These recordings sound fantastic in my room on the eps panels,an absolute joy to listen to.
I would have these recordings on my phone and listen to them when I was out and about ,you would never know they were recordings of my panels.
Steve.
I looked back to page 114 and remembered that I nearly bought one of these ear speakers ,but managed to keep my fingers off the button 😁
the last thing I need is another panel.
anyway I noticed on page 115 I made some recordings from an MA download using some various old eps panels I had lying around.
these are live acoustic recordings in a church I believe , which comes across very well with eps.
These recordings sound fantastic in my room on the eps panels,an absolute joy to listen to.
I would have these recordings on my phone and listen to them when I was out and about ,you would never know they were recordings of my panels.
Steve.
I understand Steve. I just started with panels last year and built 4 models with the ideas for many new testings... Going back to the page 114/115 I also saw the link to MA records. I have download the "sampler download" (hi res on going) and had a quick listening. Very good records, some strange tracks... but for sure very pleasant with panels (3mm plywood). It is like a window opened on the room it was recorded. And I am sure not to be at the best possibilities of the panels (walls proximity, no sub...). Some of those records should be recommended as a kind of "standard" to share listening impressions.
During this listening I was disturbed by a parasitic noise on my right panel (a static... sorry not sure of the English word). After investigation, I found it was a washer because of a loose or poorly tightened nut (I use screws and nuts to fix the exciter on a piece of plywood). Well it is fixed. Some varnish to add for blocking the nuts or replace them by nylstop version.
Christian
Steve,
I understand your experience is to say a proximity measurement is not necessary a view of what we can have at distance. Is my understanding correct?
Do you have some recommendations for a measurement set up that leads to understand what is belonging to the panel itself and what is belonging to the room? Long time ago when I was trying to measure standard loudspeaker and not having things like a laptop, umik1, REW, I was used to measure at 30cm (1ft?) 15° off axis.
In parallel to you second post (following this one), I saw going back to page 114/115 the different recommendations to use a sub to fill the frequencies let say below 300Hz. I read somewhere (where? always terrible for the memory all those posts!) that your panel plays in full range, your TLs coming in addition to fill the missing bass. Is it like that?
Christian
Steve,
The canvas are now in a second location and I have now a much better sound. So in my first listening something else modified the sound : the first room, the electronic... I made also a test by putting a "wall of melamine sponges" just behind the panels. While listening, I found the sound better but not obvious improvement at the measure. Auto-persuasion or incorrect measures? To be check. I don't think my panels are too tight. I will listen more carefully to the vocals in the next days. Vocals seem more discriminant than other sounds. I will try also thinking to measure in conditions closer to yours. It do it at few centimeters and about 2m (almost listening position) where you have often 1ft, 3ft, 10ft.
Christian
Christian.
the links in my posts on page 115 show very clearly the panel room response from my seating position 12ft from the panels.
as can be seen ,the large dip below 300hz is very destructive, but is different from different types of panel and room interaction.
If you take the measurement from the near field 1ft, you would think you had a very good full range panel, but that isn't the case at 12ft.
This panel in my room needs support from my TLs to produce a good room response below 300hz as shown in my other pictures.
I have shown panels with large suck outs in the 100hz to 300hz or So .
My TLs not only help drive the room better in this area but the combination of the 4 speakers (2 TLs + 2 panels) similar to using multiple subs, smoothes the room response nicely.
even with my large panels I never let them run full range down below 50hz or 80hz as strong electronic music can start the panels and exciter vibrating uncontrollably.
I like to be able to play my panels at realistic sound levels , without them starting to walk across the room ,which they have done some times !
Steve.
Ps
I will try to answer some of your other questions ,when I get time, but it is late.
the links in my posts on page 115 show very clearly the panel room response from my seating position 12ft from the panels.
as can be seen ,the large dip below 300hz is very destructive, but is different from different types of panel and room interaction.
If you take the measurement from the near field 1ft, you would think you had a very good full range panel, but that isn't the case at 12ft.
This panel in my room needs support from my TLs to produce a good room response below 300hz as shown in my other pictures.
I have shown panels with large suck outs in the 100hz to 300hz or So .
My TLs not only help drive the room better in this area but the combination of the 4 speakers (2 TLs + 2 panels) similar to using multiple subs, smoothes the room response nicely.
even with my large panels I never let them run full range down below 50hz or 80hz as strong electronic music can start the panels and exciter vibrating uncontrollably.
I like to be able to play my panels at realistic sound levels , without them starting to walk across the room ,which they have done some times !
Steve.
Ps
I will try to answer some of your other questions ,when I get time, but it is late.
Another quasi promising update....
I found the USB connector for my ZOUDIO 4ch amp, so I was able to apply filters and remeasure. Green is the first raw measurement, red was the best I could do with initial EQing, blue is the final target I'm trying to achieve.
Good news: I was able to get the panel to run a lot flatter. Sounds much better. Still gets low. With adjustments, sounds a lot more musical and dynamic.
Bad news: I used the brand new exciters. Same measurements basically which is good for consistency but also bad. Still some wonky stuff going on up top. Current setup (exciter stuck to panel with double sided tape) seems to have a nasty notch at 12K I can't fix. This may be a property of the exciter more than the panel as my EPS panels had a very similar high frequency response (small peak at 9K, big notch at 12K, slight rise from there)
Also I think the big low end peninsula from 2K down might be some active EQ in the amp. Just more impetus to get my TPA3255 amp set up.
I will probably have to mount the exciters directly to the panels with screws which could be interesting. I imagine getting rid of the metal feet might have a meaningful effect on response. I am HOPING it wakes up the top end. I will get some hardware this week to play with. Even if it doesn't fix the issue there's enough headroom in my amp and the DSP to get things OK. So it's looking better. Still bummed I can't get that initial response though, that was a sweet curve.
I found the USB connector for my ZOUDIO 4ch amp, so I was able to apply filters and remeasure. Green is the first raw measurement, red was the best I could do with initial EQing, blue is the final target I'm trying to achieve.
Good news: I was able to get the panel to run a lot flatter. Sounds much better. Still gets low. With adjustments, sounds a lot more musical and dynamic.
Bad news: I used the brand new exciters. Same measurements basically which is good for consistency but also bad. Still some wonky stuff going on up top. Current setup (exciter stuck to panel with double sided tape) seems to have a nasty notch at 12K I can't fix. This may be a property of the exciter more than the panel as my EPS panels had a very similar high frequency response (small peak at 9K, big notch at 12K, slight rise from there)
Also I think the big low end peninsula from 2K down might be some active EQ in the amp. Just more impetus to get my TPA3255 amp set up.
I will probably have to mount the exciters directly to the panels with screws which could be interesting. I imagine getting rid of the metal feet might have a meaningful effect on response. I am HOPING it wakes up the top end. I will get some hardware this week to play with. Even if it doesn't fix the issue there's enough headroom in my amp and the DSP to get things OK. So it's looking better. Still bummed I can't get that initial response though, that was a sweet curve.
Cheapvega.
If you could state the position of the microphone in regard to the exciter,distance ,and panel material ,this could help with understanding what is going on , in the plot.
on the green line the response is good from 2k to 10k (mostly within plus or minus 2.5db ) but after 10k this could be a suck out problem caused by the exciter ?
In an attempt to boost the response above 10k you seem to have caused the peak at 9k on the red line.
If this is a near field response of the exciter ? I would not try to use eq to sort this problem out ,as this could be very misleading.
Steve.
If you could state the position of the microphone in regard to the exciter,distance ,and panel material ,this could help with understanding what is going on , in the plot.
on the green line the response is good from 2k to 10k (mostly within plus or minus 2.5db ) but after 10k this could be a suck out problem caused by the exciter ?
In an attempt to boost the response above 10k you seem to have caused the peak at 9k on the red line.
If this is a near field response of the exciter ? I would not try to use eq to sort this problem out ,as this could be very misleading.
Steve.
Christian.
The most important measurements to you are the ones in your seating area.
Measuring the response around the room in different positions is interesting ,but trying to alter these other responses with EQ could mess up your seating area responses?
At about 1m in front of the panel ? you should get a pretty good idea of the response the panel is putting out into the room .
But the further back and around the room you will see what the room is doing too the response.
When I used to make recordings of my panels I would use the 1m point for my microphone placement ,I felt this was best compromise.
If the microphones were placed further back into the room they would exaggerate the room response( noise) and sound awful .
I usually take an average response around my seating area, not a single point response ,as this could also be misleading ?
Steve.
The most important measurements to you are the ones in your seating area.
Measuring the response around the room in different positions is interesting ,but trying to alter these other responses with EQ could mess up your seating area responses?
At about 1m in front of the panel ? you should get a pretty good idea of the response the panel is putting out into the room .
But the further back and around the room you will see what the room is doing too the response.
When I used to make recordings of my panels I would use the 1m point for my microphone placement ,I felt this was best compromise.
If the microphones were placed further back into the room they would exaggerate the room response( noise) and sound awful .
I usually take an average response around my seating area, not a single point response ,as this could also be misleading ?
Steve.
Thank you Steve
I keep in mind your advise:
- keeping the panel in full range down to 50/80Hz, not below
- add the sub to fill the holes and benefit of multi sources in bass. I read somewhere else it keeps the slam of low medium (probably a question of time alignment in the response).
- if record to share a result, 1m, not to far in the room.
Christian
@spedge all measurements had the mic basically 2-3cm in front of the exciters. I was more just trying to see the speaker's natural response and seeing how much EQ could affect that. I will do a full measurement + EQ from listening positions once these are installed.
I got some more measurements, now with the exciters screwed directly to the panel rather than stuck with squishy double edged tape. I tried 2cm (yellow), 20cm (blue) and 1m(green). There are def some room interactions at distance, but again I am not testing in a similar room or for room interactions. Just seeing what the driver can do.
After some eyeball EQing I got the following at 20cm (red vs raw in blue):
Still definitely some tweaking to do, and the filters to fix the high end were heavy. There is a serious hole at 12K; there is a good 20dB of boost there and there is still a bit of a hole. But music sounds much better now and I can see where I need to tweak to get things flat.
That is all kind of secondary though. The main takeaway for me is these things can legitimately cover the full range, only needing a subwoofer to fill in the lowest of the low end. There is still a little "distance" and coldness in the sound, but I think some of that is from the holes at ~500 and ~3500 (the latter also being a weird hole). But it's all tunable.
Next step is to get my TPA3255 chip and ADAU1701 wired up so I can see how these run with more headroom. Gonna go ahead and order 4 panels for my kitchen. I'm sold.
I got some more measurements, now with the exciters screwed directly to the panel rather than stuck with squishy double edged tape. I tried 2cm (yellow), 20cm (blue) and 1m(green). There are def some room interactions at distance, but again I am not testing in a similar room or for room interactions. Just seeing what the driver can do.
After some eyeball EQing I got the following at 20cm (red vs raw in blue):
Still definitely some tweaking to do, and the filters to fix the high end were heavy. There is a serious hole at 12K; there is a good 20dB of boost there and there is still a bit of a hole. But music sounds much better now and I can see where I need to tweak to get things flat.
That is all kind of secondary though. The main takeaway for me is these things can legitimately cover the full range, only needing a subwoofer to fill in the lowest of the low end. There is still a little "distance" and coldness in the sound, but I think some of that is from the holes at ~500 and ~3500 (the latter also being a weird hole). But it's all tunable.
Next step is to get my TPA3255 chip and ADAU1701 wired up so I can see how these run with more headroom. Gonna go ahead and order 4 panels for my kitchen. I'm sold.