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

[Crackie]

The bars and disc on the Pioneer tweeter are used to modify the phase of the tweeter's output. If you search for tweeter phase plugs rather than waveguides it should all become clear.

HTH

[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

[Monty Python]

Sounds like marketing BS to me - here's what it says on the Pioneer website:

"Soft Dome Tweeter with Wave Guide for Increased Sensitivity"

How does a waveguide increase sensitivity? A waveguide for a tweeter is a lot more complicated that just sticking a bit of plastic in front of it.

[Crackie]

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

[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

[Crackie]

vx220 said:

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

The short tube will not be helping at all; it will restrict HF dispersion. Windscreen reflections can be used to advantage so I'd not be too concerned about these for now. As you say, not too difficult to try.

Good luck.

[Frybywire]

http://www.diyaudio.com/forums/multi-way/7833-acou...

[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?

[Crackie]

vx220 said:

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?

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.

[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.

[Crackie]

App should be fine.......let us know how you get on. Good luck.

[TonyRPH]

Crackie said:

<snip>
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.

Instead of Arta (which needs a licence to save data) you could try HolmImpulse which is freeware and fully functional.

[Crackie]

TonyRPH said:

Crackie said:

<snip>
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.

Instead of Arta (which needs a licence to save data) you could try HolmImpulse which is freeware and fully functional.

I've been using Holimpulse for a few years, that's why I included links to both ARTA and Holmimpulse in my post; they're both great, particularly considering they are freeware. I use Holmimpulse for time aligning and ARTA. LIMP is great for Thielle Small measurements which Holmimpulse doesn't do.

I use the free version of ARTA and just use a screen capture when I want to keep information. The full ARTA licence is only 79 Euros which I think is great value considering what it is capable of. ARTA is used by Philips, Sony, Siemens, Nokia, LG, Samsung, Microsoft, Analog Devices, Beyerdynamic, Genelec, Ford, General Electric, Bose, Logitech, Visaton, Revox, Hi-Fi Choice

[TonyRPH]

I'm sorry Crackie - my attention span is slipping - I didn't even notice the link in your OP.

As you were..

[Crackie]

No probs Tony......... remember ARTA and HOLM in this thread back in 2013 ? Page 2

http://www.pistonheads.com/gassing/topic.asp?h=5&a...

[TonyRPH]

You have a far better memory than I! That thread had completely escaped my memory.

As I mentioned in that thread, I had been using Fuzzmeasure - and having recently sold my MacBook, this week I went off looking for a Windows alternative - if only I had remembered that thread.

I found the link to HolmImpulse via the DIY Audio site.

I rarely do much with speakers these days, I prefer to leave it to the professionals!

[Funk]

So there's a reason my tweeters have these other than physical protection?


(not my pic)

I always assumed it was to protect the metal-dome tweeter from damage - a soft-dome one would usually pop back into shape with some gentle heat if pressed gently but a metal one will crinkle (even with the guard you still see lots of fked A-series tweeters - they were bespoke to the A-series range and there are no spares now either).

[Crackie]

TonyRPH said:

I rarely do much with speakers these days, I prefer to leave it to the professionals!

I'm not involved with developing speaker professionaly any more but was very fortunate to have access to £25K worth MLSSA and Breul & Kjaer gear and a private anechoic chamber from 1995 to 1999. I used CLIO systems from 1999 to 2015; Far East suppliers mostly prefer LMS measurement kit. If you have 100,000 or so Euros to spare you might fancy a full Klippel laser measurement system. https://www.klippel.de/

Edited by Crackie on Saturday 23 January 21:36

[Crackie]

Funk said:

So there's a reason my tweeters have these other than physical protection?


(not my pic)

(even with the guard you still see lots of fked A-series tweeters - they were bespoke to the A-series range and there are no spares now either).

Have you tried Paul Seago at http://www.audioloudspeakers.co.uk/boultons.shtml ?

He makes new KEF B110 woofers using the original tooling and jigs tooling and I believe he may have purchased some redundant Celestion stock when the Ipswich factory stopped making Hi-Fi speakers.