Tweeter "waveguides"

[vx220]

https://encrypted-tbn0.gstatic.com/images?q=tbn:AN...

The above tweeter has two bars across the front of the dome, and what looks like a contact lens in the centre.

I assume this all acts to disperse the sound over an increased area/angle? I'm guessing if it was mounted with the bars aligned horizontally it would widen the angle of sound (for want of a better description, like a lighthouse beam?) to the left and right of the tweeter?

I have tried a fair bit of Google, but "tweeter waveguide" seems to generate a lot of info and pics of horns and external waveguides, nothing about ones in front of the speakers

FWIW, Pioneer do call the waveguides in their literature, but we all know how much BS there is in the audio world, so it could just be a fancy grill!

Any help appreciated,struggling to get logged on to "Talk Audio", feel free to cross post for me!

Cheers

[vx220]

Really does help, thank you

From a quick read, the bars are acoustically transparent (or close to...) and the lens expands the angle of the sound, reducing the difference between on- and off-axis listening?

Thank you

[vx220]

Crackie said:

The Pioneer tweeter in the picture has a waveguide and a phase plug. The active part of the tweeter is the pale blue dome, the plastic flare running from the dome to the periphery is the waveguide; this effectively horn loads the tweeter and increases sensitivity. The two plastic ribs and central circular feature is the phase plug.

Using a short flare in front of a tweeter dome is common practice to increase sensitivity.

Here are a couple of links to tweeters using similar techniques
http://www.dynavox.com/3.5inch-Round-4oz-8-ohm-20m...
http://www.wilmslow-audio.co.uk/monacor-dt-74-diam...

Edited by Crackie on Monday 23 November 21:54

Thanks again. I currently have those tweeters in a mkiii mr2, in the standard upper-door position. Unfortunately, they fire down a short tube before the sound has to find a way through the OEM grill. I wonder if this contributes to the slightly shouty nature? It's nothing compared to the OEM mylar ear destroyers that Toyota fitted, but wondering if moving them out of there would help? Only place I can think of is the A-pillars, in the little pods Pioneer supply, but I'm worried about windscreen reflections

We'll see, not too difficult to try

[vx220]

Nearly two months later(!), I've made a start

I was worried that by moving the tweeters to the actual grills that I'd be narrowing my stage, so I used that as an excuse to buy a miniDSP processor so I can time-align all four front speakers. I needed a new amp anyway, as my old one had just died, so I bought a four-channel to allow me to run active.

Almost finished moving the tweeters, lots of filing and sanding to get the Pioneer cups to sit inside the Toyota cups.

Hoping that not having the tubes in front of the tweeters makes them less harsh, if that doesn't help I now have the benefits of lowering the gains on just the tweeters and/or very precisely EQing the mid/high range to reduce the shouting...

I guess this needs moving to our "In Car Electronics" forum? When did that change from Sat Nav?

[vx220]

Crackie said:

Minidsp gear is great , I use a 4x10 on one of my home systems. If you've gone to the expense of new amps and dsp you might be interested in setting everything using measurements rather than by ear.

The following hardware and software is capable of making reference quality measurements for relatively little cost. This level of measurement quality, using B&K or MLSSA, would have cost over £10K a few years ago. £110ish now.

http://tascam.com/product/us-122mkii/
http://www.behringer.com/EN/Products/ECM8000.aspx
http://www.artalabs.hr/index.htm
http://www.holmacoustics.com/holmimpulse.php

£110-£115 will enable you to make your own accurate TSP, SPL, phase, group delay, distortion, time alignment, energy time curve, spectrum analysis, Spectral Decay, RTA measurements.

Thanks, may be a next step. For now, I have an RTA app for my phone, that will take a calibration file from a Dayton mic, so hopefully for £26 all-in I can get pretty close. Obviously I can only set frequency response using EQ and crossovers, but I think that'll do me for now.

[vx220]

Project on hold, MR2 stolen...