March 7, 2011

Waveguide shootout 2 - measurements

See introduction to this event

If you aren't sure what these charts mean, you might like to read about how to read them. They aren't hard to understand once you know what you are looking for. Reading directivity plots >

XT1068 + Faital Pro


We measured the waveguide only, but you can read about this speaker that I have written about previously. It was built in one weekend. Econowave deluxe >


You can see here that the axial response is not flat and that this combination isn't offering constant directivity.


Normalised. Once the axial response is corrected, it turns out that this combination is better than it appeared. At both ends, the response narrows. Compare to our previous measurement:


This indicates that our measurements aren't totally consistent. 

I have spent about a week with this speaker, and I can say that the Faital compression driver sounds better than I recall during our first session. It may be that some driver break-in has improved the sound, or it may be that normal listening is different to our test in which we put the speakers through some torture tests, playing music quite loud that would expose any harshness. Further, this time a high quality mid driver was used and the speaker was placed in an acoustically treated room with bass traps and servo subs. All this suggests it should sound better than in a test designed to show up flaws. 

Overall this is a very nice speaker with a clean sound and great dynamics. Compared to my Miniwaves, the midrange clarity is apparent but the top end is quite similar.

The performance with the DE250 is noticably better. 

Normalised you can see that while the waveguide narrows response at the top, this driver performs better on the bottom end. 

Dayton 10" and DE250


The response here is not as good as what was achieved previously with the Selenium.

The performance is fair. In the normalised plot below, you can see the response gradually narrows with increasing frequency, but from 2.7 - 5k that smooth transition is interrupted. 


Dayton 12" and DE250


Normalised:


Very similar to the 10" version.

Pyle YD-L033 + DE250



Some of the best results of the day were achieved with this combination.


Normalised:


For most of the range, the response is about as good as it gets. 

The Pyle YD-L033 along with bolt/screw adaptors are available locally at DJ city

This waveguide accepts screw type drivers, so we had to use an adaptor, which needed to be modified. The hole needed to be made larger and the screw holes were not big enough. Not exactly a nice neat solution out of the box. 


Acapella Plasma tweeter


This is an unusual and exotic tweeter that requires it's own power supply and has a crossover built in. It is a super tweeter with a very extended top end response as shown below.


The directivity control in the top octave is very good, but lower down it varies considerably. 

6 comments:

  1. Hey Paul, great blog you've got going here. I'm planning to try out a few things you've been demonstrating. I've been following the econowave thread and maybe will try something similar to the 4Pi speakers. Where do you get the JBL clone wave guides in melbourne? Are they the $20 wave guides from DJ city? Thanks, Paul

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  2. Paul, thanks. Those aren't mine, but yes I think they were from DJ city. That said, check out the StereoNet classifieds because Antripodean is selling a pair. Those guides could probably do with some attention ie something added to the back of them to make them a bit more inert. That isn't expensive or difficult. One of the guys at our little event mentioned he has used lead flashings with good results. I think one of the best choices is actually a QSC which is a bit hard to get, it's an oblate spheroid apparently and a group are getting some. Not sure in which forum that is being organised! I can find out if you like, but it would probably cost a bit more than this one.

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  3. You can find it here:

    http://www.djcity.com.au/products/yd-l033-horn-abs-resin-162x303x107mm_1025.html

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  4. Thanks Paul. Which thread does it list the group buy for the QSC waveguide? I've seen on audio karma Zilch mentioned he bought the horn from this http://www.qsc.com/products/speakers/hpr/hpr152i.htm for $15.

    I'll checkout stereonet. I've never posted there. I have an account, but somethings wrong with my settings and whenever I try to post, it says i don't have permission, never got around to asking the admins about it.

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  5. Cool. I just finished prototype of my 2-way hi-sens loudspeaker: DTQWT enclosure holding 2x12" extended range paper woofers (push-push dipole) topped with Monacor DT300 with complementary waveguide. First impressions are eye-wetting for clarity and openness of the sound. Thanks, guys, your article showed me the next measurements will be for directivity.

    Actually I think measurements of directivity must become industry standard for loudspeaker quality estimation and become part of marketing. They are colourful and very obvious show problematic zones if such exist. The crowd would like it >:)

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