Just for clarity, let's repost that whole paragraph
I do not consider this a high performance project, and the drivers I am using are not high end… they fall towards the affordable end of the spectrum. The cabinet design does not use highly profiled shapes to minimize diffraction effects, it uses a basic edge bevel to achieve acceptable diffraction performance. So it did not make sense (to me) to expend the effort to use butyl damping material to minimize resonances and signature.
I do not consider this a high performance project, and the drivers I am using are not high end… they fall towards the affordable end of the spectrum. The cabinet design does not use highly profiled shapes to minimize diffraction effects, it uses a basic edge bevel to achieve acceptable diffraction performance. So it did not make sense (to me) to expend the effort to use butyl damping material to minimize resonances and signature.
No, certainly not. In some of my projects, I do aspire to maximum performance. But in other projects, such as this one, I have other goals.
I, for one, am impressed by your willingness/ability to fabricate enclosures of this standard as a one-off. The first speaker I ever built was a 2 way speaker with Scan-Speak drivers, without any bracing 🤔
Things you do in your twenties…🤣
Jim, you may “not consider this a high performance project, and the drivers (you are) using are not high end”
I’ve very familiar with the drivers you’re using. Apart from the limitations based on SPL/size, with your design methodology and rigorous processes, I think this will be a high performance boxed speaker.
Things you do in your twenties…🤣
Jim, you may “not consider this a high performance project, and the drivers (you are) using are not high end”
I’ve very familiar with the drivers you’re using. Apart from the limitations based on SPL/size, with your design methodology and rigorous processes, I think this will be a high performance boxed speaker.
A design is nothing more than a mix of the sum of choices, constraints, skill, knowledge and budget.
When the end result was met with satisfaction, we have reached succes.
Whatever that satisfaction could be.
If not, we didn't succeed.
It completely confuses me why "high-end" would be an end goal?
Most importantly because it's an extremely vague word and idea to begin with.
Let alone even the need to defend it.
Second, a slightly less optimized diffraction doesn't all of a sudden break the entire performance and design.
If that would be the case, 99% of speakers would fail.
It changes the compromises somewhat at best. (That's a fact, not an opinion)
In the end this project was done with looking and considering for all the best options possible.
Within the set of constraints, budget and personal choices.
In my book that's excellent engineering. 👍🏻
I wish half of my customers would think that way.
When the end result was met with satisfaction, we have reached succes.
Whatever that satisfaction could be.
If not, we didn't succeed.
It completely confuses me why "high-end" would be an end goal?
Most importantly because it's an extremely vague word and idea to begin with.
Let alone even the need to defend it.
Second, a slightly less optimized diffraction doesn't all of a sudden break the entire performance and design.
If that would be the case, 99% of speakers would fail.
It changes the compromises somewhat at best. (That's a fact, not an opinion)
In the end this project was done with looking and considering for all the best options possible.
Within the set of constraints, budget and personal choices.
In my book that's excellent engineering. 👍🏻
I wish half of my customers would think that way.
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Will you be publishing the crossover details when you finish the build, I'm sure others would like to make this speaker
Yes. I intend to document it with a level of detail such that someone else can replicate it.
The plywood I am using has 5 inner core plies and a face ply on both sides. The inner core plies are probably poplar, and the outer face plies can be anything from birch and maple (least expensive) to walnut and quarter-sawn white oak (most expensive). This is cabinet grade material usually used in furniture, kitchen cabinets, display cases, etc. My supplier typically stocks Canadian plywood, but this particular material is made by Murphy in Oregon. Since I am going to veneer the entire cabinet, I chose the least expensive face veneer, which happened to be birch.
My supplier also stocks Baltic birch plywood. It is an excellent material, it machines well, and has outstanding screw-holding ability. It is also quite heavy because all plies are birch veneer (birch is a very strong but dense wood). For comparison, the 18mm BB plywood I have in my shop has 11 core plies along with the two face plies. I have used Baltic birch plywood on past projects, and I may use it again in the future, but having used both kinds of plywood, I do not believe that BB has a performance advantage. From the standpoint of strength, durability, and screw-holding, yes it has a definite advantage. From the standpoint of resonance control and low acoustic signature, it has no real advantage. In the past, the BB plywood in North America came mostly from Russia, but I am not sure where the current supply is coming from.
So for this project, I am using the standard cabinet grade plywood both for cost reasons and to keep the weight down.
My supplier also stocks Baltic birch plywood. It is an excellent material, it machines well, and has outstanding screw-holding ability. It is also quite heavy because all plies are birch veneer (birch is a very strong but dense wood). For comparison, the 18mm BB plywood I have in my shop has 11 core plies along with the two face plies. I have used Baltic birch plywood on past projects, and I may use it again in the future, but having used both kinds of plywood, I do not believe that BB has a performance advantage. From the standpoint of strength, durability, and screw-holding, yes it has a definite advantage. From the standpoint of resonance control and low acoustic signature, it has no real advantage. In the past, the BB plywood in North America came mostly from Russia, but I am not sure where the current supply is coming from.
So for this project, I am using the standard cabinet grade plywood both for cost reasons and to keep the weight down.
Thanks!
I guess quality Will vary. I bought some post pandemic and though it had many layers, face of veneer was paper thin, like no Way to make a strong bond. Also had some disgusting junk in it which had bad smell when cutting it.
Sounds like a fine plan to use standard ply in your Project 🙂
I guess quality Will vary. I bought some post pandemic and though it had many layers, face of veneer was paper thin, like no Way to make a strong bond. Also had some disgusting junk in it which had bad smell when cutting it.
Sounds like a fine plan to use standard ply in your Project 🙂
Hello,
I am more interested in following the process not so much in copying the crossover.
Perhaps include the measurement methods and the results / numbers put into the VituixCAD software. Plus the reiterations of listening and measurement.
Thanks DT
Dear @DualTriode
As you have already had measurement experience, have you had an opportunity to read the excellent text tutorials on how to take dual axis measurements: 0-360 in horizontal plane and vertical plane, for every 10 degrees, as provided by @kimmosto
This the biggest change in methodology or process from traditional on-axis +/- a few off axis measurements, and IMHO this one of the most powerful features of VituixCAD2.
These Quick Start manuals are available for variety of measurement suites eg. ARTA, REW, SoundEasy, & Clio at URL:
https://kimmosaunisto.net/
If you do not have one of the above, I would suggest starting with REW as it is free to download and try, and Donate ware if you like, like VituixCAD2. If you are used to your own setup, the ideas are the same.
It can be challenging to follow the Quick Start guide, perhaps because they are ultra-dense and do not contain any superfluous/extraneous words. This is both an advantage (only ~16 pages) and disadvantage (limited explanatory notes) however, may I suggest one method that worked for me?
Read it in sections (critical steps)
a) system set up: get set up for semi dual or dual channel measurements
b) set up with a rotating turntable for full 360 degree measurements in horizontal plane, and vertical plane
c) take “Far field measurements” and do this for your tweeter/HF element.
Only after one has taken the dual plane measurements and managed to import them into VituixCAD2 correctly, then should one proceed with the 2nd half of the Quick Start guide, as you will need to use other built-in VituixCAD tools eg. Diffraction, Merger
Best regards.
PS. Start a Conversation with me if you’d like to take this off-line.
As you have already had measurement experience, have you had an opportunity to read the excellent text tutorials on how to take dual axis measurements: 0-360 in horizontal plane and vertical plane, for every 10 degrees, as provided by @kimmosto
This the biggest change in methodology or process from traditional on-axis +/- a few off axis measurements, and IMHO this one of the most powerful features of VituixCAD2.
These Quick Start manuals are available for variety of measurement suites eg. ARTA, REW, SoundEasy, & Clio at URL:
https://kimmosaunisto.net/
If you do not have one of the above, I would suggest starting with REW as it is free to download and try, and Donate ware if you like, like VituixCAD2. If you are used to your own setup, the ideas are the same.
It can be challenging to follow the Quick Start guide, perhaps because they are ultra-dense and do not contain any superfluous/extraneous words. This is both an advantage (only ~16 pages) and disadvantage (limited explanatory notes) however, may I suggest one method that worked for me?
Read it in sections (critical steps)
a) system set up: get set up for semi dual or dual channel measurements
b) set up with a rotating turntable for full 360 degree measurements in horizontal plane, and vertical plane
c) take “Far field measurements” and do this for your tweeter/HF element.
Only after one has taken the dual plane measurements and managed to import them into VituixCAD2 correctly, then should one proceed with the 2nd half of the Quick Start guide, as you will need to use other built-in VituixCAD tools eg. Diffraction, Merger
Best regards.
PS. Start a Conversation with me if you’d like to take this off-line.
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Progress will be delayed for the next couple of days. I roasted my laptop, my fault completely... I was trying to take a frequency response scan of the cheap class D amp I use for testing, while connected to various drivers. Somehow I stupidly ran the power output of the amp into the headphone jack of the PC. I smelled burning electronics, and the laptop went dead.
After 48 hours and $913 I am back in business with a new laptop and all of my data recovered. But I still need to reinstall all of the specialized software that we all use... Arta, VituixCad, Hypex filter design, MiniDSP, DATS, etc...
My solution to the amp problem is I am going to dump the cheap amp get a better one which has a flat frequency response regardless of load impedance.
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7575669
@DualTriode - I will try to document my mental process when taking measurements and designing a crossover.
j.
After 48 hours and $913 I am back in business with a new laptop and all of my data recovered. But I still need to reinstall all of the specialized software that we all use... Arta, VituixCad, Hypex filter design, MiniDSP, DATS, etc...
My solution to the amp problem is I am going to dump the cheap amp get a better one which has a flat frequency response regardless of load impedance.
https://www.diyaudio.com/community/threads/compact-low-cost-active-3-way-speaker.402812/post-7575669
@DualTriode - I will try to document my mental process when taking measurements and designing a crossover.
j.
Hello hifijim,
I am sorry hearing about the smoke leaking out of your laptop computer. I had similar happen to my AP 2225 analyzer. The smoke made my eyes water and pocketbook hurt.
If along the way if if you could look at the bass distortion measurements and midrange IMD as you adjust the weights on your passive radiators. Adjusting the PR weights may effect the VC excursion of the mid-bass driver and distortion measurements with it.
Are you measuring the woofer excursion during this project?
Thanks DT
I am sorry hearing about the smoke leaking out of your laptop computer. I had similar happen to my AP 2225 analyzer. The smoke made my eyes water and pocketbook hurt.
If along the way if if you could look at the bass distortion measurements and midrange IMD as you adjust the weights on your passive radiators. Adjusting the PR weights may effect the VC excursion of the mid-bass driver and distortion measurements with it.
Are you measuring the woofer excursion during this project?
Thanks DT