First trials of active horn speaker

[morricab]

Hello Morricab

Glad you like them!



Exactly it's not. What you get is better low level resolution like the the noise floor suddenly getting lower.



Well you have to remember the when they originally went with the "diamond" surrounds it was done with aluminum. The problem with the aluminum was the surrounds added a lot more stress and they were failure prone. That's what lead to the use of titanium which is much more fatigue resistant but not as well self dampening as the Aluminum they replaced.

To take some of the harshness away from the Ti all you have to do is add aquaplas to damp the diaphragms. Makes a definite difference for the better.

Rob

Well, I have now gone back to the old Beyma CP350Ti to listen again because I was finding the blend between the horn and the Supravox problematic with the Radian. The resolution and detail is superb but there is a lack of upper mid/lower treble power that made all that resolution somewhat spotlit. Also, I found the listening less relaxing and a bit nervous and the soundstage and imaging somewhat flattened. Switching the amps to 16 ohms (the drivers are 16ohms) helped a bit but still was not the harmonious blend I was getting with the other horn/driver combos.

Switching back to the Beyma I was like "ahhh". No obvious drop in resolution really but more space between instruments and there is more room in the music for instruments to breathe. That nervousness is essentially gone. I am wondering if I am reacting to a mismatch in the horn or if the Radian is simply higher in distortion, which at these levels shouldn't matter but who knows? The Beyma is rather famous for having VERY low distortion for a CD. I will continue to work with the driver and perhaps try it another small horn I have to see if it was a mismatch (the Beyma, for example did not sound at all right in the 18 sound XT120 but works great in the Iwata 600) with the horn. Maybe the Radian wants something more like a SEOS style waveguide or perhaps a more traditional horn like Tractrix? Ideas?

The CP350Ti has a pure Ti diaphragm, which has no audible breakup (also the distortion stays low right through the whole bandwidth)...not hard at all. The CP755Ti has a mylar surround attached toTi diaphragm but doesn't have audibly better highs and distortion is actually a bit higher despite a much bigger magnet and larger diaphragm. Seems they figured out how to use Ti without the need for Aquaplas...although that might take things even further.

 

[bonzo75]

Brad, you already have a Radian reference sound with the Universum.

 

[morricab]

Brad, you already have a Radian reference sound with the Universum.

Yes, but not in my system. That said, I don't love the Universum as much as you do...but it doesn't have to do with the horns. I also like very much the sound of the Radian coax drivers as used in the Live Act Audio speakers.

I am not giving up on it but it could be a horn mismatch or they need more breakin or the crossover/equalization needs work. I didn't measure yet. Just my first impression was "hey nice resolution" but then I started to hear the flatness and a somewhat "busy" sound. The Beyma on first listen sounds more "right".

Now, I am pretty sure you haven't heard the Beyma driver but I can tell you that you definitely shouldn't discount it without hearing it. Jadis thought it was good enough to be used in their Eurythmie and Eurythmie II speakers, for example.

 

[Joao@altheamusica]

Well you have to remember the when they originally went with the "diamond" surrounds it was done with aluminum. The problem with the aluminum was the surrounds added a lot more stress and they were failure prone. That's what lead to the use of titanium which is much more fatigue resistant but not as well self dampening as the Aluminum they replaced.
To take some of the harshness away from the Ti all you have to do is add aquaplas to damp the diaphragms. Makes a definite difference for the better.
Rob

When you modify the drivers then you have to measure them in the plane wave tube because it's another driver now and you should know how they're working after the modification (frequency, impedance etc.)

 

[morricab]

So, after going back through all the discs I was using to evaluate the Radian/Iwata combo with the Beyma/Iwata combo, it is clear to me what was bugging me listening to the Radian. The superb sense of depth and intense 3d imaging returned when I switched back to the Beyma. Body returned that helped with dynamic punch. It was much more relaxing and at the same time more engaging and less "busy" so the music made more sense with less effort. As I said, initially I found the Radian impressive with its apparent transparency and resolution. But I found listening to it fatiguing. I tried adjusting the level down and then lost too much resolution, up in between was better but still not right.

To say this was unexpected is an understatement. Having heard Radians deliver the goods in many systems I am now wondering what is the issue. Could the horn mismatch be that bad? Do the drivers need a huge amount of breakin? Clearly I need to make some measurements to see if the balance is completely off. I also noted that they roll off pretty fast below 1Khz, whereas the Beymas go down to nearly 500Hz. Perhaps I need to bump up the crossover to 1.2 or 1.5Khz to get them in a more comfortable performance zone? Let's see but I will be working on them to try to bring them up to where I thought they should be.

But it again reinforces my feeling that the Beyma is not just a good driver it is a GREAT driver. Regardless of whether or not the Radian's stay, the Beymas will for sure stay.

I might also try an 18 sound 1.4 inch driver to match with the XT1464 to see if a combo like that can sound better than the CP755Ti.

The new 300B amps are not the quietest but adequately so. They sound wonderful on the horn though...really holographic like would expect from a good 300B amp that isn't working hard at all.

 

[Robh3606]

When you modify the drivers then you have to measure them in the plane wave tube because it's another driver now and you should know how they're working after the modification (frequency, impedance etc.)

Hello Joao

If you use the large format JBL drivers you can get Ti diaphragms ribbed un-coated, smooth un-coated and smooth coated. The differences on a plane wave tube will be hard to see as there is a slight reduction in level. You see it more in the time domain so figure ETC, Wavelet, CSD, Waterfall. It's a light thin coating that is sprayed on so it adds a little mass.

Rob

Clearly I need to make some measurements to see if the balance is completely off.

Hello Morricab

You really should remeasure and go from there. I had a similar experience building my 1400 Array changing from Aluminum to Be. Comparing say a 2431 vs 2435 so aluminum vs Be same exact driver there is a significant change in spectrum measured on the same horn.

Rob

 

[Duke LeJeune]

The resolution and detail is superb but there is a lack of upper mid/lower treble power that made all that resolution somewhat spotlit. Also, I found the listening less relaxing and a bit nervous and the soundstage and imaging somewhat flattened."

Are you using the same crossover? If so, that might have something to do with it.

 

[morricab]

Are you using the same crossover? If so, that might have something to do with it.

Yes, but with the level adjusted. It is still a 2nd order LR at 1khz. However, this might be straining the Radian as it rolls off just below 1khz. The Beyma doesn't start to roll off until around 600Hz. Maybe I will bump it to 1.2 or 1.5 and see if it works some magic.

 

[bonzo75]

For 600 Hz you need the 950 or 951. Or 850

 

[bonzo75]

Also your iwata Fc is 600, so you will need to cross near 1200 or you will need another horn that goes lower

 

[morricab]

Also your iwata Fc is 600, so you will need to cross near 1200 or you will need another horn that goes lower

Autotech says 900Hz.

 

[bonzo75]

Autotech says 900Hz.

You should have it at 2* Fc. It can go lower but that is what is ideal

 

[morricab]

You should have it at 2* Fc. It can go lower but that is what is ideal

Well, I will look into it anyway, whether the driver or the horn, it is not happy with the Radian at 1Khz. I will leave it at that then also for the Beyma and again do the apples to apples comparison.

 

[bonzo75]

Well, I will look into it anyway, whether the driver or the horn, it is not happy with the Radian at 1Khz. I will leave it at that then also for the Beyma and again do the apples to apples comparison.

It can't be apples to apples. For example, if you want to compare vdh to koetsu, you might need to change tonearm or VTA or something, not have everything constant

 

[bonzo75]

Brad, just looking at 475 as I have only heard it as a tweeter on uni. You really cannot use it under 2k I think. Ask kodomo, he is probably using it close to 5k. Theoretically it should work in your horn from 1200 but there seem to be reports of users finding it irritating below 2k

 

[morricab]

Brad, just looking at 475 as I have only heard it as a tweeter on uni. You really cannot use it under 2k I think. Ask kodomo, he is probably using it close to 5k. Theoretically it should work in your horn from 1200 but there seem to be reports of users finding it irritating below 2k

Well, I can add another data point to that...it did become irritating...I was clearly hearing distortion that was flattening the images and sound stage. Fortuneately, it is easy for me to play with the XO.

The Surpavox sounds superb in the lower/mid treble so bumping up the XO to 2, 3 or even 10Khz still sounds good.

 

[Robh3606]

Yes, but with the level adjusted. It is still a 2nd order LR at 1khz. However, this might be straining the Radian as it rolls off just below 1khz. The Beyma doesn't start to roll off until around 600Hz. Maybe I will bump it to 1.2 or 1.5 and see if it works some magic.

Hello Morricab

You should really do your own measurements on your horn and work from there. Looking at their published graphs I would go for a 1.5k. With L/R you are 6db down at 1k from the slope looks too low.

Rob

 

[morricab]

Hello Morricab

You should really do your own measurements on your horn and work from there. Looking at their published graphs I would go for a 1.5k. With L/R you are 6db down at 1k from the slope looks too low.

Rob

Hi Rob
I plan on making measurements but just wanted a first listen as is. It didn’t work so well now time to roll up the sleeves and do some work.

That being said, I did try 2khz with the Beyma driver and this seems to work very well. I will measure and tune that first. Then swap drivers and measure again. Make necessary adjustments, listen adjust measure etc.

 

[Duke LeJeune]

Yes, but with the level adjusted. It is still a 2nd order LR at 1khz. However, this might be straining the Radian as it rolls off just below 1khz. The Beyma doesn't start to roll off until around 600Hz. Maybe I will bump it to 1.2 or 1.5 and see if it works some magic.

The recommended minimum crossover frequency of the Radian is 1.2 kHz, and imo this makes sense, as its impedance peak (and presumably its resonant frequency) seems to be about 850 Hz.

It sounds to me like your crossover doesn't include any equalization of the driver's response. If that is the case, then whichever driver has the best innate frequency response on the horn you're using will probably "win".

Ime frequency response is what matters most, then once the frequency response is good, the Beryllium diaphragm's freedom from breakup starts to be a worthwhile improvement. But Beryllium (and other exotic diaphragm materials) can't compensate for having an audibly worse frequency response.

 

[Joao@altheamusica]

Hello Joao
If you use the large format JBL drivers you can get Ti diaphragms ribbed un-coated, smooth un-coated and smooth coated. The differences on a plane wave tube will be hard to see as there is a slight reduction in level. You see it more in the time domain so figure ETC, Wavelet, CSD, Waterfall. It's a light thin coating that is sprayed on so it adds a little mass.
Rob

Hello Rob
thanks for the input, yes of course that's correct to measure that as well. My first attempt would be to measure the driver in the PWT and then waht you mentioned