8'' two-way any reason why not?

[Wolf]

Re: 8'' two-way any reason why not?

Hi Wolf,

I posted the same reply on project MAX, Just ignor. I have used the M8a in some large 3 way speakers and maintain it has some of the best bass for the size and price for any driver i have heard. It works in a relativelly small box and better in a big one. I dont know why it is not used on a wider basis!!! Is the tweeter as good as you say?

The DX25 does what it was intended for. It's not as sweet as the AirCirc, but for 1/10th the cost, I guess it doesn't have to be! It is rather articulate, and engaging.
Later,
Wolf

[Stu]

Re: 8'' two-way any reason why not?

Hi Wolf,

I posted the same reply on project MAX, Just ignor. I have used the M8a in some large 3 way speakers and maintain it has some of the best bass for the size and price for any driver i have heard. It works in a relativelly small box and better in a big one. I dont know why it is not used on a wider basis!!! Is the tweeter as good as you say?

[Wolf]

Re: 8'' two-way any reason why not?

Hi Wolf,

Any chance you could post a bill of materials for the crossover for the Project MAX, coils, caps ets. I could not find coils with the dc that you detailed in you xover plan. Look forward to building this one

The schematic states some resistors may need to be added, as I assume you mean the Tweeter shunt-coils. I believe they are 0.3mH/0.4mH, and I used 1 ohm 10W resistors in series to get relatively close. Sometimes they measure a bit higher, and you can measure the resistors to get even closer to the specs I listed.

I intend on posting a writeup when they are complete, as they are not yet, and then a cut-list, BOM, and everything else will be listed. This is the first project that I'll have to list a full cut-list due to complexity, and the xover is fairly complex too.
Thank you for your interest!
Wolf

[Stu]

Re: 8'' two-way any reason why not?

Hi Wolf,

Any chance you could post a bill of materials for the crossover for the Project MAX, coils, caps ets. I could not find coils with the dc that you detailed in you xover plan. Look forward to building this one

[brianpowers27]

Re: 8'' two-way any reason why not?

Ok... Initial setup... more to come later.

I spun off from this thread to discuss 8" 2 way xo topologies.

http://techtalk.parts-express.com/showthread.php?p=1597677#post1597677

[ctbowman]

Re: 8'' two-way any reason why not?

If you were on acid.....
:rolleyes:
Wolf

Or if you suffer/benifit from synesthesia.

[ctbowman]

Re: 8'' two-way any reason why not?

Yes, yes, yes... AUDAX!!!
That's what I'm looking for now... Audax [and Vifa] 6.5" and 8" midwoofers!!!

GC

check out zalytron.com for audax drivers on sale.

[DDF]

Re: 8'' two-way any reason why not?

I will honestly admit that is quite a bit more measurement than I usually do. I would really like to create a turntable for this project. WHen I measure, I will start a thread to combine all of the info so others can see what I am doing. I imagine I might have time in a few months. Right now I am in the midst of a few non-speaker projects.

I know the feeling.

The additional measurements are quite easy, once you have the set up its just a few more angles.

For the vertical measures, lay the speaker on its side and turn them into horizontal measures.

They don't have to be at the exact angle unless you plan on going back later and verifying the work, but even then close is good enough. We used a turntable at work but I personally never felt it would help with hobby measures.

I put together a very simple excel spreadsheet that inputs the driver layout and the mic distance and then it spits out the mic height or position for various angles, and calculates the position of the first boundary reflection in the impulse. I found it useful for knocking measures off quickly. Send me a PM if you'd like a copy.

In the first stage driver characterization of any design, I'll very often take up to 50 measurements, free field over many angles along with distortion, near field, near field distortion. I find it very helpful during later voicing exercises.

Dave

[brianpowers27]

Re: 8'' two-way any reason why not?

Brian,

I look forward to your opinion!

I've tried my method in a couple different environments. I have my preconceptions about where it excels, and when it wouldn't, but would rather have them challenged, or reinforced independently. Not only that but I'm hoping it works for you, and results in more accurate and enjoyable speakers!

As mentioned in past email, for the room you'll be doing your listening in I recommend measuring the drivers at 0, 15, 30 and 60 degs plus at the floor notch bounce angle, at standing up angles and at side wall bounce angles and give them strong consideration when designing the xover.

Dave

I will honestly admit that is quite a bit more measurement than I usually do. I would really like to create a turntable for this project. WHen I measure, I will start a thread to combine all of the info so others can see what I am doing. I imagine I might have time in a few months. Right now I am in the midst of a few non-speaker projects.

[DDF]

Re: 8'' two-way any reason why not?

Dave,

I finally got this 8" 2way project back from my friend. This winter I plan to try out the method you are describing. I plan to disconnect the drivers from the passive xo and fashion 2 or 3 different models and apply them to different dcx2496 presets. I then plan to switch back and fourth a few times to see what I am missing.

I will likely try something like 2500hz 2nd order and or a 1st order assymptoting to a 3rd order... per your email.

Brian,

I look forward to your opinion!

I've tried my method in a couple different environments. I have my preconceptions about where it excels, and when it wouldn't, but would rather have them challenged, or reinforced independently. Not only that but I'm hoping it works for you, and results in more accurate and enjoyable speakers!

As mentioned in past email, for the room you'll be doing your listening in I recommend measuring the drivers at 0, 15, 30 and 60 degs plus at the floor notch bounce angle, at standing up angles and at side wall bounce angles and give them strong consideration when designing the xover.

Dave

[brianpowers27]

Re: 8'' two-way any reason why not?

Robert,

Most if not all drivers will have some edge or cone resonances that make life interesting at 1 to 3 kHz. FWIW in my case I found that, in these sort of cases, ignoring the curve and theory and voicing it with a bit higher and shallower xover most often works better than driving the xover lower and steeper, even if there are some lumps on axis. YMMV!

It does push the woofer up higher into a region where it beams more, but that's exactly what you want: you want the total off axis output from 3 to 5 kHz to be a combination of the overly strong tweeter and the underly strong woofer, so it blends better and is smoother than if the off axis from 3 to 5 kHz was dominated by the overly strong tweeter.

By using these low Q xovers, the slight dip from 3 to 5 kHz and xovers that aren't in phase on axis, it won't sound like 6kHz and up is hot, because the room will contribute to fill in the slight 3 to 5 kHz depression.

FWIW, I really can't overstress this too much.

I think this is the "secret sauce" to making a two way with 6" or larger mid woofers sound good in a small to med room. You won't hear it as much in a DIY meet in a huge room, but you would in the real at-home installation.

It's not getting much uptake here, but I haven't heard anyone try it and report back, other than George at North Creek who raves about it.

I think you guys are really missing out. I know if I put it on a fancy web site with graphs etc it would get some traction, but I've put this particular idea out there on the page (since the late 90s!!), it doesn't need the eye candy.

Try it before discounting, I think you'll like it.

Dave

Dave,

I finally got this 8" 2way project back from my friend. This winter I plan to try out the method you are describing. I plan to disconnect the drivers from the passive xo and fashion 2 or 3 different models and apply them to different dcx2496 presets. I then plan to switch back and fourth a few times to see what I am missing.

I will likely try something like 2500hz 2nd order and or a 1st order assymptoting to a 3rd order... per your email.

[DDF]

Re: 8'' two-way any reason why not?

Yes, you can shallow out the woofer a bit, but neither mine nor Wolf's driver (esp. his) will do this super well. 2.5K and 4.2K are fair irregularities in woofer response on the F8 and probably to be avoided.

...

Raising the XO frequency further narrows the dispersion of the 8" woofer too, so you kind of end up in a closing circle, where you pick one issue to keep or another

Cheers / Robert

Robert,

Most if not all drivers will have some edge or cone resonances that make life interesting at 1 to 3 kHz. FWIW in my case I found that, in these sort of cases, ignoring the curve and theory and voicing it with a bit higher and shallower xover most often works better than driving the xover lower and steeper, even if there are some lumps on axis. YMMV!

It does push the woofer up higher into a region where it beams more, but that's exactly what you want: you want the total off axis output from 3 to 5 kHz to be a combination of the overly strong tweeter and the underly strong woofer, so it blends better and is smoother than if the off axis from 3 to 5 kHz was dominated by the overly strong tweeter.

By using these low Q xovers, the slight dip from 3 to 5 kHz and xovers that aren't in phase on axis, it won't sound like 6kHz and up is hot, because the room will contribute to fill in the slight 3 to 5 kHz depression.

FWIW, I really can't overstress this too much.

I think this is the "secret sauce" to making a two way with 6" or larger mid woofers sound good in a small to med room. You won't hear it as much in a DIY meet in a huge room, but you would in the real at-home installation.

It's not getting much uptake here, but I haven't heard anyone try it and report back, other than George at North Creek who raves about it.

I think you guys are really missing out. I know if I put it on a fancy web site with graphs etc it would get some traction, but I've put this particular idea out there on the page (since the late 90s!!), it doesn't need the eye candy.

Try it before discounting, I think you'll like it.

Dave

[brianpowers27]

Re: 8'' two-way any reason why not?

Hopefully dumb Q:
Do you just hit your targets and leave it in a design?
*OR*
Do you hit your targets, remove the targets and tweak?

It just looks like you optimized for your targets, and nothing beyond that in the graphs.
Curiousity...
Wolf

I think I usually shoot for the targets. I find my ears are much less reliable from listening to listening than the graph. It turns out that the one I favored has similar characteristics as the one DDF described above. I find that if I am tweaking much of anything it is usually the padding of the tweeter.

RElative alignment of the acoustic centers likely facilitated the pureness of the model against the reality of a textbook formulation. My design is almost dead on LR4 at the tweeter axis.

[robert]

Re: 8'' two-way any reason why not?

For me on this project: aim for targets, listen, remove targets, and tweak. When it was dead-on LR4, I didn't like the sound of it much. At Iowa, OK was good enough since it was 2AM the night before the drive

Cheers / Robert

[Wolf]

Re: 8'' two-way any reason why not?

Hopefully dumb Q:
Do you just hit your targets and leave it in a design?
*OR*
Do you hit your targets, remove the targets and tweak?

It just looks like you optimized for your targets, and nothing beyond that in the graphs.
Curiousity...
Wolf