Synergy horn build

[skatz]

John

Do you have a link to Bill Waslo's spreadsheet for the synergy horn? I have a terrible time every time I try a search on DIYaudio, usually don't find things I know to be there!

[jhollander]

This is not going to make MWAF this year. I'd be happy if I made the Design team end in September.

I made a bunch of tests with phase plugs, unfortunately none with the F model. What I found was that I could not get the shape right or close enough to the dome to stop the destructive interference. Most of the tweeters I tested were 1 inch dome that were recessed behind the face plate. The XT and RS that performed better also had very little recess.

Note the Wolf added a grill and phase plug to his TL labs tweeter. He might have some interesting measurements. If you are following the wave guide thread, I do think the edge overlap is important.

[6thplanet]

Could you use your own "phase plug" on the F tweet?

[skatz]

John
How is this coming, will you have it for MWAF?

[jhollander]

Horn response models for the GRS 4FR mid and DCS165 woofers. The roll off on the woofer does not represent a ported enclosure. The key here is to make sure the modeled construction of the driver ports into the horn provide enough overlap for the x-o.

[jhollander]

From my foam core model, a few tweeter tests

[jhollander]

Chuck, I'll check the construction. The best measured tweeters have a phase plug or deflector that change the wave shape to reduce the destructive interference in the 8K to 11K range. The XT25 and the RS28A measured the best.

[isaeagle4031]

The F might actually be a bit better John. It's natural top end rise can help offset the natural drop from the horn loading.

[jhollander]

The plan is for a 3-way. Tweeter is the RS28A (I mistakenly ordered the F ) I'll post some of the measurements tomorrow. The mid is the GRS 4FR-8, but I'm a bit concerned with the sensitivity as the published specs don't match a 91 dB sensitivity. The woofers are the DCS165-4 subwoofers a pair per side.

With the offset loading horn loading of the mid and woofer it's pretty tough to do a 2-way unless you use a small full range driver as the tweeter.

[spasticteapot]

I once saw a rather clever implementation using Aura NSW2s for midrange. At $10 each, it'd probably get you down to 500hz.

[skatz]

Is the plan for this to be a two way? I know Tom Danley did a three way horn using 5" closed back mids. Not sure why though.

[dcibel]

I couldn't tell you the first thing about Synergy horns, but I know Bill Waslo has put a lot of information up on the DIYAudio forum.

[KEtheredge87]

Hey John, looks interesting. I'll be excited to watch this one progress and learn from you!

[jhollander]

For my last design team build I've decided to do a Synergy horn build. There are some technical challenges so this build could go on for a while. I'm trying to keep this simple enough to be reproducible.

The design goal (other than to make a Synergy horn), is to design the speaker for home use. As this is for home use at reasonable spl levels, I want to use a conventional tweeter (first challenge). Reasonable SPL levels mean I can also use a single midrange driver (challenge #2).

I'm using Bill Waslo's Synergy horn spreadsheet to get me started. I will not be using the waist banding flare. I'm also using Horn Response to model the offset drivers in the horn.

I've built a foam core board model for tweeter testing and have wrapped the testing up last week, so I've order parts. Attached is the current drawing.