Scanspeak 7000 in waveguide...

[bushmeister]

So I thought I would share some of my results from some of my recent experiments.

I currently have a set of three-way speakers which sound excellent, but crossover a Volt mid-dome (VM752) to a scan-speak 7000 ring radiator.

These are excellent drivers, but due to their operating ranges require a crossover from 3000-3500Hz.

Due to the 3" mid dome being horn loaded it starts to beam about 2600hz, whilst the ring radiator starts to beam at approx 4000hz.

This obviously creates some mild deviation in the power response off access with some 'tweeter bloom' between 3000-4000hz.

So I thought I would try loading the scanspeak into a waveguide. I choose the monacor WG-300 as it seemed to have a nice fit.

Here is a comparison with the 'naked' scanspeak polar, versus the waveguide loaded one. These measurements are without any corrective EQ at all.

The waveguide does appear to drop the directivity to about 2200hz, but it looks like it will require some serious EQ and playing around to get a nice polar....

 

[AllenB]

You won't be able to EQ the polars, the best you can do with them without changing anything might be to choose the best listening axis. What do you suspect is causing the 0 degree wiggles, is the waveguide about 3cm deep where it rounds back?

 

[bushmeister]

Yep - not looking good at the moment.
I should probably try mounting it properly on a test baffle for measurement - it's currently just sat in a cardboard box!

A promising start with the nice fit......shame the measurements aren't so nice!

 

[AllenB]

That would explain some. I think it is promising. I don't know that a ring radiator doesn't want a phase plug but still promising compared to without the waveguide.

 

[TMM]

It should smooth out a bit once you get it flush mounted in a rigid baffle - I suspect the peaking at 3kHz will come down a little and the 6kHz area will fill in more.

It will probably also help to fill in the back of the waveguide to give you a flat mating surface to put a thin foam gasket and seal the tweeter to the waveguide properly:
7100-waveguide

 

[mbrennwa]

Any updates on this? I would be interested how the Scanspeak ring radiators do in a waveguide. See here (VM752!) and here.

 

[wesayso]

Too bad Dave Pellegrene's results are missing in action. He had some interesting results, including for the ring radiator tweeters.
a random result from google using his name

(See first posts in that thread)

 

[Zvu]

Here are some measurements of a good implementation with Vifa XT:

Test Peerless / Tymphany XT25TG-30/04 (XT-300/K4) am Waveguide WG-300 / PCT-300 – Heissmann Acoustics

 

[mbrennwa]

Sorry for necrobumping, but this group buy for a waveguide that fits the Scan Speak tweeters might be interesting to some of you.