Just wanted to point out that you probably meant "phase plug" here, instead of "waveguide".
Wowo101,
The Tannoy Definition Install 12" clearly shows high frequency "beaming", the pattern narrows from -4 dB 40 degrees off axis at 1000Hz to -9dB 40 degrees off axis at 10,000Hz (only about half the dispersion angle as at 1kHz), and is -20dB at the VHF peak. That progressively narrowing response is not constant directivity at all.
Constant directivity designs for the HF co-ax compression drivers usually have expansions that are conical, the exponential (like) expansion the Tannoy Definition Install has cannot be constant directivity by design.
Art
Art,
you're absolutely right – I was already wondering about that.
In contrast, both the measurements of the Dimension TD10 by Sound&Vision (Tannoy Dimension surround speaker system Measurements | Sound & Vision) and the one posted on the Norwegian forum (Tannoy Dual Consentric) seem much more CD-like, as far as I can tell.
Is it possible that Tannoy is using expansions that different in their different speaker lines, or am I missing something in the measurements of the (some 10 years old) Dimensions?
Looking at the Tannoy Dimension TD10 response, it too has a progressively narrowing HF response, that fact noted in the review wowo101 linked.
Horns that are not limited to the constraints of using the speaker cone as an extension of the HF horn can use a pinched diffraction throat as used by the JBL 23xx series "bi-radial" horns with curved horn walls to achieve constant directivity.
Horns designs like the Tannoy can't pinch the throat, so exhibit progressively narrowing HF response, but don't create throat diffraction.
Every design has it's compromises...
Here at the house I've had a series of speakers:
Gedlee Summas, Vandersteens, Kef UNI-Qs, B&C coaxes, and DIY Synergy horns.
Every one of them had their own pluses and minuses:
1) The Summas are dynamic and easy to listen to, but require a big room. Due to the large center-to-center gap, they sound better at a distance than close up. And the cabinet is hu-mon-gous
2) The Vandersteens image great, but don't get loud. Basically you add more power and they don't get any louder.
3) The Kef UNI-Qs remind me a lot of the Vandersteens, but they're tiny and affordable.
4) The 5" B&C coaxes pretty much do everything right. Why did I stop using them? I've heard the 8" B&C coaxes and I felt that the 5" units are on a whole 'nother level.
5) The Synergy Horns seem like they could be The Holy Grail. But the cabinets tend to get huge, the crossover is complex, and they're easy to screw up. I should probably stick with the 5" B&C coaxes but the perfectionist in me pursues the Synergy Horn.
I just ordered another set of Kef coaxes today. For $50 they're fun to mess around with.
By the way, the $40 Fostex 3" full range might sound better than the Kef UNI-Q. I can't decide. It's a really nice driver and gives the coaxes a run for their money.
Gedlee Summas, Vandersteens, Kef UNI-Qs, B&C coaxes, and DIY Synergy horns.
Every one of them had their own pluses and minuses:
1) The Summas are dynamic and easy to listen to, but require a big room. Due to the large center-to-center gap, they sound better at a distance than close up. And the cabinet is hu-mon-gous
2) The Vandersteens image great, but don't get loud. Basically you add more power and they don't get any louder.
3) The Kef UNI-Qs remind me a lot of the Vandersteens, but they're tiny and affordable.
4) The 5" B&C coaxes pretty much do everything right. Why did I stop using them? I've heard the 8" B&C coaxes and I felt that the 5" units are on a whole 'nother level.
5) The Synergy Horns seem like they could be The Holy Grail. But the cabinets tend to get huge, the crossover is complex, and they're easy to screw up. I should probably stick with the 5" B&C coaxes but the perfectionist in me pursues the Synergy Horn.
I just ordered another set of Kef coaxes today. For $50 they're fun to mess around with.
By the way, the $40 Fostex 3" full range might sound better than the Kef UNI-Q. I can't decide. It's a really nice driver and gives the coaxes a run for their money.
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For wide dispersion coaxials, consider the Beyma 12XA30Nd and 15XA38Nd (my avatar pic). They start with a short steep conical horn stub followed by intentional circumferical diffraction egde to a much flatter conical section finally extended by the cone. The don't measure nice but they sound quite good to me and the bass driver has very practival TS parameters to get along without extra sub.
Nevertheless I came to like the big Tannoys 15" better.
Nevertheless I came to like the big Tannoys 15" better.
I have good experience with the BMS 12C362. When I'm not as lazy as I'm right now, I'll try to download a response graph showing on axis, 15 and 45 degrees off axis responses. It's not immaculately straight, but quite good among it's peers. The irregularities in the HF response are mainly kept inside 5 decibels. Due to phasing problems I still have a 5-6dB dip between 1,5 to 2,5 kHz.
This 12" coax doesn't go very low, but does sound quite good. In some respects I even slightly prefer it to the much loved Tannoy 15" Monitor Golds. And I do love the Tannoys...
This 12" coax doesn't go very low, but does sound quite good. In some respects I even slightly prefer it to the much loved Tannoy 15" Monitor Golds. And I do love the Tannoys...
More measurements
I finally got some measurements for the PHL coax mentioned in the very first post. Dieter Achenbach of Achenbach-Akustik was so kind measure his Point P25, which uses the 10" PHL X25-3491 and a 1" 18sound HD1050, crossed at 1.4 kHz.
First are frequency responses for (roughly) 0°, 15°, 30°, 45° and 60°, measured from 40cm and 1/3-octave smoothed. (Bass emphasis and disproportionally strong fall-off at 60° are probably due to the short measurement distance.)
Second is frequency response and phase at 0°, measured from 105.5 cm distance, windowed and (again) smoothed.
The response seems balanced and acceptably smooth: The dips at 1.3 and 4 kHz should be fixable via DSP since they appear under all angles; the dips around 6 and 10 kHz seem to be less easy to control, but they disappear beyond 30° and are quite high up in frequency.
The HF portion of the response seems to be quite constant in directivity up to 5-6 kHz beyond which this combo, again, starts to beam.
What do you guys think about the combo, especially when compared to the alternatives mentioned and discussed before?
I finally got some measurements for the PHL coax mentioned in the very first post. Dieter Achenbach of Achenbach-Akustik was so kind measure his Point P25, which uses the 10" PHL X25-3491 and a 1" 18sound HD1050, crossed at 1.4 kHz.
First are frequency responses for (roughly) 0°, 15°, 30°, 45° and 60°, measured from 40cm and 1/3-octave smoothed. (Bass emphasis and disproportionally strong fall-off at 60° are probably due to the short measurement distance.)
Second is frequency response and phase at 0°, measured from 105.5 cm distance, windowed and (again) smoothed.
The response seems balanced and acceptably smooth: The dips at 1.3 and 4 kHz should be fixable via DSP since they appear under all angles; the dips around 6 and 10 kHz seem to be less easy to control, but they disappear beyond 30° and are quite high up in frequency.
The HF portion of the response seems to be quite constant in directivity up to 5-6 kHz beyond which this combo, again, starts to beam.
What do you guys think about the combo, especially when compared to the alternatives mentioned and discussed before?
I've seen the 15 in person, and the transition from this machined throat pole piece is not smooth. It has an abrupt edge where it meets the cone. It sticks out about 1/4" from the cone. I couldn't figure out why either. I thought maybe to accomodate cone movement. Nicely machined though.
I've been playing around with a pair of Ciare 12's for about a year. It looks similar to the Beyma and has fairly good on/off axis response. I switch out between these and seos 12 based speakers. The seos is very smooth but I keep coming back to the coax. It just sounds more natural. I thought diffraction in the coax would put it out of competition but so far that hasn't been the case.
The Ciare's are crossed at 1k LR48 nude with a stack of ultratouch behind them over boxed 18's. I've tried the seos plus various mid/basses in boxes and nude with insulation behind and draped over to combat diffraction. Crossover between 1k and 1.5k with various slopes.
I've also tried transient perfect crossovers for both using overlapped LR12 but cone breakup was worse than the subtle change in linear phase perception. Need FIR for that.
They both sound very good and the smooth frequency response of the seos is audible over the coax, but the coax just sounds more real. Instruments sound more like they're there rather than coming from a speaker.
Personal preference and implementation will play a big role in choosing between formats though. Kind of have to try both. Synergy horns do seem like the right path to follow from my experience.
I've also tried transient perfect crossovers for both using overlapped LR12 but cone breakup was worse than the subtle change in linear phase perception. Need FIR for that.
They both sound very good and the smooth frequency response of the seos is audible over the coax, but the coax just sounds more real. Instruments sound more like they're there rather than coming from a speaker.
Personal preference and implementation will play a big role in choosing between formats though. Kind of have to try both. Synergy horns do seem like the right path to follow from my experience.
Ciare coax
Hi Ernie,
Can the compression driver be substituted or is it fixed?
Best,
Kris
Hi Ernie,
Can the compression driver be substituted or is it fixed?
Best,
Kris
The PHL charts look pretty good to me for a coax. I think it would be a solid choice.
I would really like to see measurements of the BMS. They do look quite nice. Just to point out I only use active crossovers. It's just so much more practical to get proper alignments dialed in. Getting the proper delay is critical for good results.
While we're on the subject I would also like to try the 15NCX1000 from 18 Sound.
Edit: The driver is fixed for the Ciare. It's a good one though.
I would really like to see measurements of the BMS. They do look quite nice. Just to point out I only use active crossovers. It's just so much more practical to get proper alignments dialed in. Getting the proper delay is critical for good results.
While we're on the subject I would also like to try the 15NCX1000 from 18 Sound.
Edit: The driver is fixed for the Ciare. It's a good one though.
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