Fatbellies Finished, the pics and build info

[mzisserson]

Here's the final response 0,15,30,60 off axis in my room, gated to 10ms. The dip at 1K was a decision of sound vs. measurement.




Distortion



Full write up in my blog link below.

[arlis_1957@yahoo.com]

very nice.

[Mayhem13]

Excellent finish work!

[Paul Carmody]

Looks great! Wish I could hear them someday.

[jclin4]

I know first hand you design fantastic sounding speakers.

Now your cab finishing is top notch too! Looks great!

[mattp]

Beautiful speakers Mike, I love that veneer. Hopefully I'll get the chance to hear these sometime.

[mriversinco]

Very sharp finish work on those speakers!

[johnnyrichards]

I enjoy this build quite a bit, just something awesome about an 8" 2-way. Well done, sir.

[billschu]

Good for you Mike.

Question. Since you gave curves for on and off axis "in room", was that from the listening position or just in the room?

Also, since you gave the curves on and off axis, did you use just one speaker to determine that?

I usually measure "in room" from the listening position and then from the auxiliary listening positions so I'm curious as to what others do. Mine has a dip around 100Hz or so due to the room's response.

Bill

[mzisserson]

Good for you Mike.

Question. Since you gave curves for on and off axis "in room", was that from the listening position or just in the room?

Also, since you gave the curves on and off axis, did you use just one speaker to determine that?

I usually measure "in room" from the listening position and then from the auxiliary listening positions so I'm curious as to what others do. Mine has a dip around 100Hz or so due to the room's response.

Bill

All measurements are pink noise to 1W, then measured at 1M with the proper tones. I find it more important to get the off axis right at 1M than from the listening position. For me, there is a correlation to good 1M measurements and good sound at the listening position since the room is so heavily involved by then. At 1M you can see lobing if it is occurring as a direct result of the speaker vs. the room. At the point where you are 8-12' away, then you use the measuring for placement, not for response.

Anything below 300Hz it is hard to say what is in-room or not. One can argue higher as well for early reflections. I get peaks dips from the listening position as well. I believe everyone would.

[billschu]

I think folks need to spell out what they mean by "in room" for response when they measure and post just for those reasons. It's too much of a gray area.

In the case of waveguides, one needs to bump the response up a bit in order to get the power response correct so there's more need for them to measure, listen, back up, measure, listen, etc. Luckily my latest project is only using a mild waveguide which has a much smaller effect than some others but the limited vertical dispersion still allows for more gain from the mid than the tweeter. The end result if I keep the tweeter close to flat at 1m is an overall "sweet" sound at most listening positions.

Bill

All measurements are pink noise to 1W, then measured at 1M with the proper tones. I find it more important to get the off axis right at 1M than from the listening position. For me, there is a correlation to good 1M measurements and good sound at the listening position since the room is so heavily involved by then. At 1M you can see lobing if it is occurring as a direct result of the speaker vs. the room. At the point where you are 8-12' away, then you use the measuring for placement, not for response.

Anything below 300Hz it is hard to say what is in-room or not. One can argue higher as well for early reflections. I get peaks dips from the listening position as well. I believe everyone would.

[DjDisturbed]

Those really look nice, I have always liked the look of those HiVi drivers.

[brokencrank]

Wow! very nice. I'll second the "hope to hear them" sentiment and am thinking the exojam get together in Sept. would be a great place to show these off.

[mzisserson]

Wow! very nice. I'll second the "hope to hear them" sentiment and am thinking the exojam get together in Sept. would be a great place to show these off.

They will be there

[mzisserson]

I think folks need to spell out what they mean by "in room" for response when they measure and post just for those reasons. It's too much of a gray area.

In the case of waveguides, one needs to bump the response up a bit in order to get the power response correct so there's more need for them to measure, listen, back up, measure, listen, etc. Luckily my latest project is only using a mild waveguide which has a much smaller effect than some others but the limited vertical dispersion still allows for more gain from the mid than the tweeter. The end result if I keep the tweeter close to flat at 1m is an overall "sweet" sound at most listening positions.

Bill

I look forward to hearing them, Bill.

I just measure from D'Applito's methods in "Testing Loudspeakers". It seems to work just fine, and the correlation between what is measured and what I works for me.

I would measure using the same methods outside, too. In Room just explains a lot of the wiggles below 500Hz or so.

Waveguide, omni, dipole, bipole, no tweeter, 500 tweeters, it still has to sound good, even if it measures less than perfect. I can flip the phase back on the tweeter and they are near flat through the crossover, but they just do not sound as coherent that way, so I will live with a few dB dip at 900-1K.

Whatever yours measure, they measure. If they sound good, that is fine. I do urge you to post a build thread on them over in the general forum and get some feedback, the forum was a big help answering some specific design question I has on these.

[billschu]

I think we're in the same camp there although you need to hear a real waveguide speaker which measures flat at 1M in any room. Unless you've got them set up like headphones in an extreme near field situation they're going to sound extremely rolled off. That's a caveat that I know some day you will explore. You won't be able to help yourself because I know you're just so curious about it.

I've been in the same boat where a slight wiggle in the phase actually lined up with better sound and better imaging. Goes against the grain but I've been there. The MOABs are textbook however.

I never post build threads as I like to keep things to myself but I think I will this time. I'm usually doing something novel but not this time. Everything is simple and by the book. These drivers are so easy to work with. A planar tweeter is nearly textbook if the response is flat because if the smooth impedance curve and working with the Accuton has been a joy. Getting the phase to line up was a piece of cake.

What am I wrestling with now? I almost always do a BBC dip as well as have the bass a couple of db up but in this case I'm enjoying the flat midrange with great music. Having a hard time diverging from my methods as I'd like these to be a bit more forgiving with stuff like Aerosmith. Sure Patricia Barber sounds just STUNNING but you get the idea. We are in the same camp there.

If I add a filter to "tailor" the sound from 1-3Khz the Accuton is revealing enough to show how adding components can remove some of the transparency and liquidity. Next up I'll try notching the 3-6Khz range just a bit. As of right now, the response is scary smooth at 1M.

I was tempted to take the HiVi D8.8 out of the picture for something a bit more efficient but the bass from this driver is really accurate and it doesn't compress much when driven really hard either.

Guess it's time to take some pictures and save some measuremnts.

Bill

I look forward to hearing them, Bill.

I just measure from D'Applito's methods in "Testing Loudspeakers". It seems to work just fine, and the correlation between what is measured and what I works for me.

I would measure using the same methods outside, too. In Room just explains a lot of the wiggles below 500Hz or so.

Waveguide, omni, dipole, bipole, no tweeter, 500 tweeters, it still has to sound good, even if it measures less than perfect. I can flip the phase back on the tweeter and they are near flat through the crossover, but they just do not sound as coherent that way, so I will live with a few dB dip at 900-1K.

Whatever yours measure, they measure. If they sound good, that is fine. I do urge you to post a build thread on them over in the general forum and get some feedback, the forum was a big help answering some specific design question I has on these.

[cooper]

That is a beautiful pair of speakers. I love the concept.
Outstanding finish work. I bet those 8's really growl.

[billschu]

I would bet money that this is going to be the next easy to build affordable speaker that captures high end nuance, great imaging, great bass extension, a bit of a forgivable laid back nature, and small size that would be easy for folks to copy.

I know the tweeter and am using the woofer myself.

I'm thinking it's only detriment is ALSO a true positive for the speaker and that would be the midrange would be a bit soft and laid back.

This is all speculation of course but I know how picky Mike is with his sound as I was inundated with text messages over many nuance during it's development.

I know I'm really enjoying the HiVi D8.8 in my own project.

Bill

That is a beautiful pair of speakers. I love the concept.
Outstanding finish work. I bet those 8's really growl.

[spkrman57]

Those are beautiful looking spkrs!

Regards, Ron