Steve,
Okay, I read and re-read 346-350 about the whizzer cones, but am a bit confused. I use a Keurig coffee machine. They have a plastic container to hold the coffee grounds that is 39x45mm. There is a paper filter inside that actually holds the grounds. What do I make the cone from? I don't see a way to get the paper part out without tearing it to shreds. If you will notice, on the bottom is where the machine pierces the cup to allow the coffee water to exit. Please explain how I am to use this, or if this is a proper one to use at all. Thanks.
Okay, I read and re-read 346-350 about the whizzer cones, but am a bit confused. I use a Keurig coffee machine. They have a plastic container to hold the coffee grounds that is 39x45mm. There is a paper filter inside that actually holds the grounds. What do I make the cone from? I don't see a way to get the paper part out without tearing it to shreds. If you will notice, on the bottom is where the machine pierces the cup to allow the coffee water to exit. Please explain how I am to use this, or if this is a proper one to use at all. Thanks.
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Today I’m using a modified tectonic bmr driver. Main reasons are a larger x-max and price (half). I have described this in earlier post. They are very similar in performance excpept for the lowest frequency range where the tectonic has slight edge.
I’m using another tectonic exciter for my pure DML speaker. This one I think is very good and robust. I have pushed it really loud combined with a 15 inch woofer. This I also described in an earlier post.
Thomas
Andre, I saw this new version of exciter and I was wondering if the 25FHE2 would have a higher frequency response if it was attached to the panel without screw in adapter. There was a paper written by Ben Zenker (Convention Paper 10324) that mentioned at higher frequencies you get breakup of the voice coil. He made up a reinforcement spider that he installed inside the voice coil to improve high frequencies. I'm guessing that the voice coil on this new version would be stronger due to the additional thread, which to some degree might act as the reinforcement spider and be less prone to breakup at higher frequencies. On the other hand, it could be weaker!
Using the 25FHE2 without the screw-in adapter and attaching directly to the panel might improve the high frequency response without that big resonant peak?
You'd have to test that and let us know what you find??
When I get a moment I'll be constructing a few arb extension tubes and things and try them out on the drivers I've got here, to see what happens.
Sandasnickaren.
The 25c10 exciter is basically the same as my exciters except 8ohm.
The BMR could be an option for my proplex panel ?
Although I would mount the coil directly to the panel.
Tectonic don't seem to mind the resonant peaks above the 10k area on their exciters or BMRs, they must think it increases its high end response.
I wonder if some of my techniques would reduce this and bring up the lower frequencies a little?
The 25HFE is around the same price as the BMR unit in the UK and I don't have to cut it up , so maybe a better option?
Steve.
The 25c10 exciter is basically the same as my exciters except 8ohm.
The BMR could be an option for my proplex panel ?
Although I would mount the coil directly to the panel.
Tectonic don't seem to mind the resonant peaks above the 10k area on their exciters or BMRs, they must think it increases its high end response.
I wonder if some of my techniques would reduce this and bring up the lower frequencies a little?
The 25HFE is around the same price as the BMR unit in the UK and I don't have to cut it up , so maybe a better option?
Steve.
There is no resonance peak on the this tectonic exciter.
Yes, there is a resonance peak on the mbr driver. However it is not present when I remove the diaphragm and use it as an ”exciter”. Yes, I remove the complete diaphragm and connect the voicecoil directly to the diaphragm.
I’m buying the bmr from https://uk.rs-online.com/web/p/speaker-drivers/8765291.
’Thomas
Yes, there is a resonance peak on the mbr driver. However it is not present when I remove the diaphragm and use it as an ”exciter”. Yes, I remove the complete diaphragm and connect the voicecoil directly to the diaphragm.
I’m buying the bmr from https://uk.rs-online.com/web/p/speaker-drivers/8765291.
’Thomas
I was thinking that was the case. What are the dimensions of them? Maybe I could mush up some paper and make a paper mache whizzer from a suitable mould, or do the same with aluminum foil. It looks like a custard cup is about the right size and shape. What do you think about that idea? That might be too much work for my poor old hand, though.
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Agreed.
But there are two things going on there.
There's not just a deeper cavity, but also an added mass.
Maybe the mass plus the deeper cavity combine to produce that horrible peak.?
The original peak (without the extension) is at 15kHz.
This is brought down to 11kHz with the bigger cavity and the added mass.
But the trajectory of the peak (lower Hz and higher db) seems to hint that there's an even bigger peak, maybe with a higher Q, somewhere between 5 & 8khz???
Very decent price. These were the first exciters I tried & would still be using them if I hadn't blown one up. Then C19 hit & you couldn't get them, so I ended up with some two for £11 Chinese jobs on ebay which work surprisingly well. I may try to pick up a couple of these to try again. They benefit from easy connection too, as well as ease of connecting to a supporting spine should one wish to use one.
That looks like the TAEX25C10-8 but instead of one exciter they use 2 in parallel to make 4ohms plus a different type of outer shell plastic casing.
https://www.parts-express.com/Tectonic-TEAX25C10-8-SP-25mm-High-Power-8-Ohm-Frog-297-206?quantity=1
I waited all day yesterday for the glue to dry on this next test panel.
Using the same eps panel I glued a matchstick through the hole in the back of the exciter and through the panel.
The first picture shows the panel with the old smaller (5inch x1mm) panel in front.
The 5inch panel was made from paper machete egg box some years ago, but I never bothered to mention it as it was not a full range panel.
The panel only went down to about 400hz anyway, so the addition of the matchstick made very little difference.
Although if I remember correctly, it did improve the noise from the rear, which was quite important as it is a small panel.
I poked the matchstick in the 5inch panel just for show, as I removed it some years ago.
Pic 2 is the response with the the matchstick at about 1ft with peak above 10k.
Pic 3 is with a small pea sized blu-tack over the matchstick which reduces the peak.
Pic 4 is with a larger blob of blu-tack spread out to cover about 1/2 inch ,this reduces it even more and does a little bit of smoothing.
As the mass is not such a problem , as the matchstick , panel and exciter magnet are joined together.
The sound is good too, as with the 5 inch panel.
I should have posted this years ago.
I was thinking maybe use a spring in the center or something more flexible to increase the low end ?
Maybe central mounting with out the spider even?
It works , but how useful it will be ,I'm not sure?
Steve
Using the same eps panel I glued a matchstick through the hole in the back of the exciter and through the panel.
The first picture shows the panel with the old smaller (5inch x1mm) panel in front.
The 5inch panel was made from paper machete egg box some years ago, but I never bothered to mention it as it was not a full range panel.
The panel only went down to about 400hz anyway, so the addition of the matchstick made very little difference.
Although if I remember correctly, it did improve the noise from the rear, which was quite important as it is a small panel.
I poked the matchstick in the 5inch panel just for show, as I removed it some years ago.
Pic 2 is the response with the the matchstick at about 1ft with peak above 10k.
Pic 3 is with a small pea sized blu-tack over the matchstick which reduces the peak.
Pic 4 is with a larger blob of blu-tack spread out to cover about 1/2 inch ,this reduces it even more and does a little bit of smoothing.
As the mass is not such a problem , as the matchstick , panel and exciter magnet are joined together.
The sound is good too, as with the 5 inch panel.
I should have posted this years ago.
I was thinking maybe use a spring in the center or something more flexible to increase the low end ?
Maybe central mounting with out the spider even?
It works , but how useful it will be ,I'm not sure?
Steve
