Waveguide TMM Posted

[Zaph]

Waveguide TMM

I posted this yesterday. Note: I see a few typos I made which I will update later when I get home.

This is another design that I've posted in the quest to do "something different". It turned out pretty good. I found myself getting emotionally involved with the music I've been playing through them. That's pretty unique for someone as objective as myself.

Enjoy,
John

[Wodgy]

That's a great looking design!

One question: in most of your project descriptions, you address/discuss the feasibility of using a sealed box, but in this writeup you only mention ported alignments. Would this design be a candidate for a sealed alignment with a somewhat less deep cabinet (for greater WAF)?

[Joules]

Hey Zaph - Great waveguide work !!
Do you think it wood be posibale to use a waveguide on a mid/woofer to compensate for baffel step rolloff?

[Zaph]

Originally posted by Wodgy
One question: in most of your project descriptions, you address/discuss the feasibility of using a sealed box, but in this writeup you only mention ported alignments. Would this design be a candidate for a sealed alignment with a somewhat less deep cabinet (for greater WAF)?

The Seas CA18RNX woofers really need to be vented. In a sealed box, the best F3 is only around 90 Hz. That might be fine if you use a subwoofer, and the sub crossover can be set to 90 hz and configured for assymmetrical slopes. I pretty much don't recommend it though. The CA18RLY would be better sealed in a 14 liter box. That driver can't swap into this design however.

Originally posted by Joules
Hey Zaph - Great waveguide work !!
Do you think it wood be posibale to use a waveguide on a mid/woofer to compensate for baffel step rolloff?

A waveguide on the midwoofer is possible, but not practical. The wavelengths are way to long.

Regards,
John

[Joules]

A waveguide on the midwoofer is possible, but not practical. The wavelengths are way to long.

Yea, but have you tryed it -
Two long boards about 4-6 inches wide placed verticaly against the side edges of the baffle angled forward to resemble a wave guide.

[ooheadsoo]

Hi John.

One thing I've personally only heard with waveguides is an effect where when you walk around between the speakers, the imaging will stay relatively locked in place. Have you heard this with your design?

I'm taking a casual look at converting the floorstanding size into a stand mount by making the enclosure deeper. Any objections, assuming volumes are maintained? More to the point, any objections to mounting the port on the side of the cabinet, if it comes down to it?

One last thing - any objections to turning the speaker upside down as long as the acoustic center is at ear level?

Thanks!

[johninCR]

John,

Thanks for sharing that design, especially with the different XO topologies apparently working so well.

Instead of woofers, what would be your opinion about trying a waveguide on a small full ranger to improve the top end? eg I'm about the build the reference enclosure for the FE127 discussed in the full range forum and I was thinking about added a piece of 1" hardwood in front of the driver for a backside of the baffle mounting look. Initially I thought I'd just round over the front edge of the driver cutout, but now I'm thinking I should be more scientific regarding the shape of that taper to make it a beneficial wave guide.

[kevyjo]

Looks great zaph! I also wanted to say I've read your website and blog and found it very informative and interesting. Forgive me for being off topic, but I'm very curious, what are your opinions about series crossovers? (or maybe I should start another thread).

[Zaph]

Originally posted by ooheadsoo
One thing I've personally only heard with waveguides is an effect where when you walk around between the speakers, the imaging will stay relatively locked in place. Have you heard this with your design?

I'm taking a casual look at converting the floorstanding size into a stand mount by making the enclosure deeper. Any objections, assuming volumes are maintained? More to the point, any objections to mounting the port on the side of the cabinet, if it comes down to it?

One last thing - any objections to turning the speaker upside down as long as the acoustic center is at ear level?

Yes, I've noticed that with the imaging. Not necessarilly when walking around, but it really seems to lock in, almost a headphone-like effect.

No worries about the cabinet variations, it should work fin as long as the baffle width stays the same. Upside down would work fine but that would be one weird looking speaker.

Originally posted by johninCR
Instead of woofers, what would be your opinion about trying a waveguide on a small full ranger to improve the top end? eg I'm about the build the reference enclosure for the FE127 discussed in the full range forum and I was thinking about added a piece of 1" hardwood in front of the driver for a backside of the baffle mounting look. Initially I thought I'd just round over the front edge of the driver cutout, but now I'm thinking I should be more scientific regarding the shape of that taper to make it a beneficial wave guide.

A 1" waveguide is probably just going to cause a ragged response curve over a small range, no real benefit. In fact, I don't see a benefit on anything other than a tweeter. Woofers by nature already have directivity built in with their large cones.

Originally posted by kevyjo
Looks great zaph! I also wanted to say I've read your website and blog and found it very informative and interesting. Forgive me for being off topic, but I'm very curious, what are your opinions about series crossovers? (or maybe I should start another thread).

That's probably best for another thread. The problem is that I would never even both opening or reading that thread. ;D I don't think there's any magic in series crossovers, it's just another way arranging the components.

[ooheadsoo]

Thanks for the reply, John.

Do you think there is benefit in extending the directionality of the speaker by crossing the drivers down into the 1khz or below range (with different drivers of course) ala Dr. Geddes's implementation or SP Technology?