My test-box is coming along nicely, including freehand routed driver recesses and sort-of-straight facets :-D
Oh well, slap some wood filler in here and it'll be good as new ;-)
Also I've received Vance Dickason's "Loudspeaker design cookbook" and wow, that's an amazing trove of information.
I'm happy I started out with David B. Weems' "Designing, Building & Testing Your Own Speaker System" as that was just simple enough to get me going with the basic concepts, but LDC really is a perfect next step.
I love the section with measurements and graphs on the effects of different baffle shapes and driver placement.
I knew about diffraction, and why people did facet baffles, but seeing the graphs and measurements makes it all much more tangible.
Next up:
shaping the sub-enclosure for the Tectonic mid.
Once that's in, I should be ready to install the drivers, add all relevant damping material, hook up the wires... and hopefully be ready to start measuring the individual drivers?
Babysteps moving forward..
Oh well, slap some wood filler in here and it'll be good as new ;-)
Also I've received Vance Dickason's "Loudspeaker design cookbook" and wow, that's an amazing trove of information.
I'm happy I started out with David B. Weems' "Designing, Building & Testing Your Own Speaker System" as that was just simple enough to get me going with the basic concepts, but LDC really is a perfect next step.
I love the section with measurements and graphs on the effects of different baffle shapes and driver placement.
I knew about diffraction, and why people did facet baffles, but seeing the graphs and measurements makes it all much more tangible.
Next up:
shaping the sub-enclosure for the Tectonic mid.
Once that's in, I should be ready to install the drivers, add all relevant damping material, hook up the wires... and hopefully be ready to start measuring the individual drivers?
Babysteps moving forward..
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Exactly. If one pursues perfection they can forget where they are going. The smart thing is to know your errors so you can keep them first order, and not compound them.
I tend to pursue perfection to a debilitating degree in my hobby projects... :-/
Which either slows projects down to a crawl, or usually results in not finishing / wanting to finish it fearing it won't live up to my self-imposed standard.
Which is why I've told myself I am building a speaker enclosure "that is not the final enclosure, just a test enclosure".
This gives me the peace of mind to keep working on this enclosure without getting bummed out about mistakes / it being sub-par.
I'm building this single speaker under the guise of "once I have figured out how to make this one good, I will start again, building *two* enclosures - perfectly" ;-)
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So, about my speaker's mid-enclosure (using Tectonic TEBM46C20N-4B) quest, regarding backwave and such...
I happened to run into some Twaron Angel Hair (yay), and some Silent Coat Absorber 35.... Which is something from the car audio world and is supposed to be good at absorbing sound: Silent Coat Absorber 35 - 2 Sheet Pack – Silent Coat UK
Eventhough in the picture it looks like standard egg crate foam, it feels very different - it reacts like memory-foam (when compressed, it takes quite some time to get back to its original shape).
I have no idea about the real-world usefulness of this stuff.
I think I might just make a big mid enclosure, line it with the Silent Coat Absorber stuff, and fill it with Twaron.
Any comments about this approach?
I happened to run into some Twaron Angel Hair (yay), and some Silent Coat Absorber 35.... Which is something from the car audio world and is supposed to be good at absorbing sound: Silent Coat Absorber 35 - 2 Sheet Pack – Silent Coat UK
Eventhough in the picture it looks like standard egg crate foam, it feels very different - it reacts like memory-foam (when compressed, it takes quite some time to get back to its original shape).
I have no idea about the real-world usefulness of this stuff.
I think I might just make a big mid enclosure, line it with the Silent Coat Absorber stuff, and fill it with Twaron.
Any comments about this approach?
Did a test run on trying to make a router template for the Tectonic driver.
I used my Dremel for convenience, when doing this "for real" I'll use my DeWalt 621 router as a proper plunge router is much more stable than the lightweight Dremel.
Learned a valuable lesson.
When routing a circle, at the end where you're completely closing the circle and disconnecting it from the rest of the board, the routed out circle becomes unstable.
And since that's where the router's circle jig is centered, it might / will move and the router will move and you might route away more than you wanted.
Lesson learned:
clamp the board you're routing to another board, and glue/screw/clamp/fixate the inner part of the circle to the second board. This will make sure your center won't move at the point where you complete routing.
I used my Dremel for convenience, when doing this "for real" I'll use my DeWalt 621 router as a proper plunge router is much more stable than the lightweight Dremel.
Learned a valuable lesson.
When routing a circle, at the end where you're completely closing the circle and disconnecting it from the rest of the board, the routed out circle becomes unstable.
And since that's where the router's circle jig is centered, it might / will move and the router will move and you might route away more than you wanted.
Lesson learned:
clamp the board you're routing to another board, and glue/screw/clamp/fixate the inner part of the circle to the second board. This will make sure your center won't move at the point where you complete routing.
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Okay, it's been a while....
I have my first amplifier *almost* working correctly.
It's using a Connex 600W SMPS ( SMPS600RS | Connex Electronic ),
a Sure 3x200W T-Amp amplifier board ( Sure Electronics AA-AB35281 3x200W Class D Audio Amplifier Board - T-Amp ),
and a Dayton / Sure / Wondom type ADU1701 DSP for filtering / crossover duties. ( Dayton Audio DSPB-K DSP Kernel Board and DSPB-KE Kernel DSP Expansion 2-In 3-Out )
This means that every driver has its own dedicated 200W amp (Chinese watts though probably
).
I wired it up provisionally and everything works, but it's a bit noisy.
I need to shield the cables that go from the DSP to the Amp; a quick test showed that that solves the noise problem... So I'm making new, shielded, cables now.
Always nice - a video of the subwoofer driver in slow motion
Subwoofer driver in slow motion - Album on Imgur
I have my first amplifier *almost* working correctly.
It's using a Connex 600W SMPS ( SMPS600RS | Connex Electronic ),
a Sure 3x200W T-Amp amplifier board ( Sure Electronics AA-AB35281 3x200W Class D Audio Amplifier Board - T-Amp ),
and a Dayton / Sure / Wondom type ADU1701 DSP for filtering / crossover duties. ( Dayton Audio DSPB-K DSP Kernel Board and DSPB-KE Kernel DSP Expansion 2-In 3-Out )
This means that every driver has its own dedicated 200W amp (Chinese watts though probably
).
I wired it up provisionally and everything works, but it's a bit noisy.
I need to shield the cables that go from the DSP to the Amp; a quick test showed that that solves the noise problem... So I'm making new, shielded, cables now.
Always nice - a video of the subwoofer driver in slow motion
Subwoofer driver in slow motion - Album on Imgur
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Also I've bought a pair of Cotswold Audio BMR56XE N4R drivers:
http://www.cotswoldsoundsystems.com/specifications/CSS_Specification_Sheet_BMR56XE_N4R_r1.pdf
I read on this forum Charlie Laub had bad experiences with the Tectonics, basically that they measured radically different after a year of use...
Then I stumbled upon the Cotswolds - who normally supply professional brands like NAIM I think - and wrote them an email asking if I could buy some for personal use.
John from Cotswold was very friendly, so now I have a pair to play with
http://www.cotswoldsoundsystems.com/specifications/CSS_Specification_Sheet_BMR56XE_N4R_r1.pdf
I read on this forum Charlie Laub had bad experiences with the Tectonics, basically that they measured radically different after a year of use...
Then I stumbled upon the Cotswolds - who normally supply professional brands like NAIM I think - and wrote them an email asking if I could buy some for personal use.
John from Cotswold was very friendly, so now I have a pair to play with
Hi!
So - it's been a while....
If you read my previous posts, I had things *almost* working correctly...
Famous last words
I couldn't get it to work properly using the Sure parts. The amplifier by itself already had a lot of noise / hiss, and once I connected the DSP - even without any input connected, or *with* input connected but no sound playing - the noise / hiss was just... Awful.
I tried all kinds of cable shielding, separating / distancing the individual parts.. you name it, I tried it - but in the end, "SCHCHSHSHSHHSHSH".
The kind of "SCHCHSHSHSHHSHSH" you hear 5 meters away.
So - I figured "Buy the cheapest parts, get the worst results".
After a bit of reading I decided to order boards by 3E Audio - the DSP board, a 1x480W TPA3255 amp, and a 2x260W TPA3255 amp.
Then I went on holiday for 3 weeks. When I got back, I found out the local postal service tried to deliver the 3E audio stuff, I wasn't home, so then they sent it back to China.... :-/
Then came COVID-19 and all that jazz and I couldn't find time for this project.
But then - a few weeks ago - I found time, and ordered again...
AND TODAY IT CAME IN! \o/
Compared to anything I ever bought from China, the packaging was perfect.
The packaging feels high quality, the right connectors and cables are included..
The boards have *proper* coils on them..
I am *very* happy with what 3E Audio sent me so far...
Now I just need to find an other evening with a few hours to spare to wire it all up
So - it's been a while....
If you read my previous posts, I had things *almost* working correctly...
Famous last words
I couldn't get it to work properly using the Sure parts. The amplifier by itself already had a lot of noise / hiss, and once I connected the DSP - even without any input connected, or *with* input connected but no sound playing - the noise / hiss was just... Awful.
I tried all kinds of cable shielding, separating / distancing the individual parts.. you name it, I tried it - but in the end, "SCHCHSHSHSHHSHSH".
The kind of "SCHCHSHSHSHHSHSH" you hear 5 meters away.
So - I figured "Buy the cheapest parts, get the worst results".
After a bit of reading I decided to order boards by 3E Audio - the DSP board, a 1x480W TPA3255 amp, and a 2x260W TPA3255 amp.
Then I went on holiday for 3 weeks. When I got back, I found out the local postal service tried to deliver the 3E audio stuff, I wasn't home, so then they sent it back to China.... :-/
Then came COVID-19 and all that jazz and I couldn't find time for this project.
But then - a few weeks ago - I found time, and ordered again...
AND TODAY IT CAME IN! \o/
Compared to anything I ever bought from China, the packaging was perfect.
The packaging feels high quality, the right connectors and cables are included..
The boards have *proper* coils on them..
I am *very* happy with what 3E Audio sent me so far...
Now I just need to find an other evening with a few hours to spare to wire it all up
Now I just need to find an other evening with a few hours to spare to wire it all up
Eh.... So... life got in the way again and it took a bit more time than expected
But alas, I found time now, wired it all up, and yay, it's alive!
Right now I have the 3E Audio DSP (ADAU1701) hooked up to the 1x480W TPA3255 for the sub and to the 2x260W TPA3255 for mid and low.
I've created a simple crossover in Sigmastudio, and it all seems to work properly.
Since the Sigmastudio DSP has a max input of 1Vrms (WHY???) I put an L Pad voltage divider on the audio input (3k3 serial, 3k3 parallel) to attenuate the input signal by about 7dB to make sure the DSP won't clip.
Now I have proper sound out of the drivers. The first thing I notice is that the HiVi RT1C tweeter outputs a bit of noise; when I disconnect the DSP from the amp board the noise is 99% gone. So the DSP is raising the noise floor. It might have to do with the bad placement of the DSP (see pic above, right next to the power supply) and the fact there's no proper grounding nor shielding currently.
That said, the tweeter is quite sensitive (94dB) so I'll have to attenuate it quite a bit (by 9dB or so) to get it in useful range anyway, so the noise might not be noticeable after that.
what system7 told you stands true: I am currently evaluating my new build in an WMTMW config (not using the third 3.5 inch mid right now). I already got the the MTM portion sounding very good and only have the WW section and the box to consider for improvements (if still possible to make with the assembled boxes).
https://www.diyaudio.com/community/...d-and-tweet-output.365730/page-2#post-6838260
you need to do some measurements and modeling to get the speakers in the ballpark before fine-tuning by EQ and listening.
https://www.diyaudio.com/community/...d-and-tweet-output.365730/page-2#post-6838260
you need to do some measurements and modeling to get the speakers in the ballpark before fine-tuning by EQ and listening.
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Sorry but I'm losing track here.... what are you referring to?
Well yes, absolutely!
For now all I've got is a test-cabinet that I've built 2 years ago, with dimensions that were probably thought out for reasons and stuff.
...and right now I'm furiously going through old posts I've made here and old emails to figure out how I ended up with those dimensions
Let's put it this way - I'm very happy right now to have a working setup of [audio signal -> DSP -> 3 separate drivers -> amplifier for every driver].
Measuring / designing crossovers and filters is the next phase.
Taking into account how much time the last phase took, measuring will probably end somewhere 2024