The Uluwatu - another new Curt C design?!

[biff]

Re: The Uluwatu - another new Curt C design?!

Why don't more people rear mount, especially with odd shaped drivers? Use a bevel or roundover bit on the face of the baffle and it looks great, and is way easier than templates and such.

[Jeff B.]

Re: The Uluwatu - another new Curt C design?!

Why don't more people rear mount, especially with odd shaped drivers? Use a bevel or roundover bit on the face of the baffle and it looks great, and is way easier than templates and such.

[ATTACH=CONFIG]45491[/ATTACH]

Like Continuums? I agree.

[Jeff B.]

Re: The Uluwatu - another new Curt C design?!

When I built the Galeons with the SB13 drivers, I flush mounted them - royal PITA.
I also surface mounted a pair and measured the response - pretty much no change from the recessed ones.
So I would advise people to surface mount them.

But we don't expect recessing the midbass to change the midbass response. We do it to reduce diffraction of the tweeter's response. That's where the difference should show up.

[NyxOne]

Re: The Uluwatu - another new Curt C design?!

But we don't expect recessing the midbass to change the midbass response. We do it to reduce diffraction of the tweeter's response. That's where the difference should show up.

+1

I once did an MTM with the tweeter centered and midwoofers surface mounted I can tell you the tweeter response was very ragged.

Chuck

[jsr]

Re: The Uluwatu - another new Curt C design?!

But we don't expect recessing the midbass to change the midbass response. We do it to reduce diffraction of the tweeter's response. That's where the difference should show up.

I wonder how much of these perturbations we actually hear along with things like perfect phase alignment and such. I look at my Speedsters where the woofer is surface mounted overlapping the tweeter and the phase alignment is actually a good bit off from one another but I've never read anyone complain.

[isaeagle4031]

Re: The Uluwatu - another new Curt C design?!

I wonder how much of these perturbations we actually hear along with things like perfect phase alignment and such. I look at my Speedsters where the woofer is surface mounted overlapping the tweeter and the phase alignment is actually a good bit off from one another but I've never read anyone complain.

Paul worked the phase alignment into the crossover.

[jsr]

Re: The Uluwatu - another new Curt C design?!

Paul worked the phase alignment into the crossover.

Oh I thought the measurements he posted were of the completed speaker. The FR plot with phase shows about 60deg of phase difference between the woofer and tweeter, but I don't hear anything significant so I figured the phase difference doesn't majorly impact my perceived sound quality. Is the plot he posts on his site not of the complete speaker?

[biff]

Re: The Uluwatu - another new Curt C design?!

Like Continuums? I agree.

Exactly!

[tomlang]

Re: The Uluwatu - another new Curt C design?!

Anyone started a build of these yet?

What is the part number of the port tube?

[divdev]

Re: The Uluwatu - another new Curt C design?!

I am starting an Uluwatu build. The port is the Precision Sound Products 4" flared port. Curt is using the inner and outer port flares connected directly together. I believe that makes for a 2" effective port length.

[ReissM]

Re: The Uluwatu - another new Curt C design?!

I love reading about Curt's designs. In an effort to learn from the master, I have a few questions:


1. I added horizontal lines at 5dB intervals and also grayed out the frequencies below 100Hz. Are we looking at a measurement artifact or does it really swing 28 dB between 150 Hz to 350 Hz?





2. From about 1 kHz to 10 kHz it looks like "textbook" comb filtering. Can this be addressed with some creative baffle diffraction experimenting? Maybe further refinement of baffle shape, bevel, radius, foam or felt applied near the tweeter???

3. OR... maybe a steeper slope on the four "0.5" woofers to eliminate path length issues? (a.k.a. Constructive/ Destructive interference resulting from using multiple point sources that cover the same frequency range.)

4. I am curious if the M-T-M portion of this speaker (Woof 2 & 3) could be separated internally with a small, sealed enclosure while the other woofers (1, 4, 5, 6) thumped away in the ported portion of the cabinet?

5. Then I started wondering how the power handling would be affected by this change, as ported speakers tend to be able to take a little more power. So what would happen if a speaker utilized both? (sealed for the two woofers playing out to 2kHz, but ported for thefour "0.5" woofers being rolled off via the 7.0mH coil.)

6. Then I wondered about the transient response of such an odd combination... both ported & sealed woofers? My question is mostly concerned with the vocals and mid frequencies reproduced by Woofer #2 & #3. Does the human ear perceive the transient response differences between ported & sealed designs based on the low frequencies (30Hz) or higher frequencies (1,000 Hz)??? And would using a sealed internal section for Woofs 2 & 3 translate to "cleaner" midrange performance... or is it not worth the trouble?


Curt, thanks for your dedication to this hobby. Your designs inspire so many DIYers like me.

[curt_c]

Re: The Uluwatu - another new Curt C design?!

Adam has the kits available now!
(He was waiting on a shipment of tweeters.) I've updated my site to show the link.

Yes, the port is missing on the pics. A little miscommunication between Alejandro and myself. He has little English and I have no Spanish, so the google translator was working overtime across the pond, and some things apparently just don't translate all that well. He is addressing the port issue now, but for the time being use your imagination on the port. -Yes it does look pretty muscular with the port installed, and his enclosures are far and away better looking than mine. As also noted, my prototype did not flush mount the pincushion frames. This of course did cause some aberrations to the tweeter response, but nothing to write home about. I assumed many would also like to skip the flush mounting twelve pincushion frames if possible, -and besides; I’m lazy by nature. This driver frame also is not flat on the front side curving down at the edges, so back mounting would be problematical as well.

This design was intended from the beginning to be a replacement for the Stens, so it’s a party speaker at heart, but I think it exhibits an improvement in sound quality and imaging over the Stens as well.

As noted above, the port is just and inner and outer flare with the connecting ring. This is a 6" total length or 5" if you were to use a straight 4" PVC pipe. The flares are recommended due to the port velocity at high SPL’s.

C

[donradick]

Re: The Uluwatu - another new Curt C design?!

But we don't expect recessing the midbass to change the midbass response. We do it to reduce diffraction of the tweeter's response. That's where the difference should show up.

Sheesh, gues I should have subscribed to this thread.
Here's the response - flush mount vs surface mount SB13s - I think I also measured with the tweeter surface mounted also.
The red trace is surface mount. Fc was about 2.3K or so, so it looks like the difference is tweeter diffraction.

[bearhaus]

Re: The Uluwatu - another new Curt C design?!

I know this design is a Sten replacement but any idea what f3 these are hitting?

The Stens got down to the 50's, I'm hoping these are more of a true full range speaker....

[ryanbouma]

Re: The Uluwatu - another new Curt C design?!

Judging by the impedance sweep, they're a 35hz tune. I'm suprised they're flat to 20hz on that in-room measurement, but the db scale is quite coarse. I can't understand those graphs very well. The tweeter looks 5db hot and the polar is quite an odd shape. Am I reading those right?