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   Home » Horn-Loaded Speakers» S3 on tractrix 260 graph. (5 posts, 1 page)
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11-26-2012 Post does not mapped to Knowledge Tree
gordan
Posts 12
Joined on 01-29-2009

Post #: 1
Post ID: 18776
Reply to: 18776
S3 on tractrix 260 graph.
fiogf49gjkf0d

here's the measurement we've got from S3 on tractrix 260 horn.


the increments on the graph are 1db


it seems useful from around 450-500 to some 1.3k, but it still looks very bumpy in comparison with a number of other mid drivers aiming the same range.


not sure if the measurement was correct due to proximity of the mic from the mouth, but we certainly didn't have an anechoic chamber for more proper measurement. 


any comments?







EDIT: PS. i apologize for opening a new thread, i've actually wanted to post this bellow a S3 talk in the forum.... maybe it can be moved there ?

11-27-2012 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,486
Joined on 05-28-2004

Post #: 2
Post ID: 18778
Reply to: 18776
Irrelevant measurement.
fiogf49gjkf0d

 gordan wrote:

here's the measurement we've got from S3 on tractrix 260 horn.

the increments on the graph are 1db

it seems useful from around 450-500 to some 1.3k, but it still looks very bumpy in comparison with a number of other mid drivers aiming the same range.

not sure if the measurement was correct due to proximity of the mic from the mouth, but we certainly didn't have an anechoic chamber for more proper measurement. 

any comments?

Yes,  the bump on 1250Hz is a typical Vitavox secondary resonance if you use plastic surround diaphragms. This is normal, well, not normal but it is what it is. Read my posts and the way how I organized my MF channel in order to deal with it.   The rest of your measurement is not “still looks very bumpy” but frankly irrelevant. Why you positioned your microphone where you have positioned it? This is absolutely irrelevant location and you must have irrelevant garbage response in there. BTW, moving your microphone in that position for a few millimeters will impact response very dramatically. The S3 is a compression driver and it meant to be used with horn, so use it with horn and let horn to do it’s duty. Measure a combined response of driver with horn and you will not be able to do it by sticking a microphone in the horn mouth, unless it is where you keep your head when you are listening music.

 gordan wrote:
EDIT: PS. i apologize for opening a new thread, i've actually wanted to post this bellow a S3 talk in the forum.... maybe it can be moved there ?

PS: I do not mind to move this to the “S3 talk in the forum” but I do not know of any thread that have dedicated S3 context. Let me know into wish thread you would like to move it and I will do it.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-28-2012 Post does not mapped to Knowledge Tree
gordan
Posts 12
Joined on 01-29-2009

Post #: 3
Post ID: 18782
Reply to: 18778
OK let's have a dedicated S3 thread
fiogf49gjkf0d
OK Romy, I agree this should stay here, especially that I will probably have more observations to come as from the late January.

I didn't explain the context of S3 use in my future system. I'm awaiting for a delivery of Beyma TPL-150 which will be tested for upper mid channel, under either Raal Lazy or Fostex T825 tweeters. 

The horn system in building is aimed to work in a small room, 4.5x5m, with about 2.7-3m distance horn mouth-listener.

So I am seeking for a "fundamental" channel solution with several particular tasks. 

The obvious one is to reach at least 400hz  though for the first experiments I will not have a slower opening horn like exponential, rather several bigger tractrix profiles like 260 from the above pics or 220. I expect the later to enable 450hz loading at least.

The less obvious task is to find a low mid driver to provide rich tonal colors - I'm a bit scared what an AMT driver that goes as low as 1.2k like TPL-150 can do and if it is going to sound very sterile and devoid of lifelike dynamics just like any ribbon crossed under 9-10k i've heard does. So this is where my interest for S3 in this application comes from. However more will be known in late January when Beyma arrives.

Re above measurements, yes I was aware that measuring at 10-15cm from the horn mouth can't give the accurate results however the alternative was to move the mic to a distance where lots of reverberation and other artefacts from empty woodworkshop would create even more innacurate results. I was actually hoping to get at least some sort of vague idea what to expect just as the measurement revealed a 1.3k resonance peak and a huge dip behind it. For accurate results I would need to bring the horn into a well damped room and that's the next step, to get the 450-1.2 range as linear as (and if) possible.

If I don't get what I want from S3, the next steps would be B&C DCM50 and cone Audax PR170M0 as last resort.

Will post more soon...
11-28-2012 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,486
Joined on 05-28-2004

Post #: 4
Post ID: 18784
Reply to: 18782
Deal with MF channel first.
fiogf49gjkf0d
 gordan wrote:
I didn't explain the context of S3 use in my future system. I'm awaiting for a delivery of Beyma TPL-150 which will be tested for upper mid channel, under either Raal Lazy or Fostex T825 tweeters. 
I am not sure that I agree with that. If you plan to use Beyma TPL-150 for upper mid channel then you need to stop to think about S3, or Fostex, or anything other supporting driver for that matter and get the MF driver first as anything else shall derive from your MF channel. Your MF channel is the main channel and you need to get it first right. Then you need to find the lover MF and twitter that will be able to work with your MF. I would get your Beyma first. Get comfortable with it and ONLY than would be thinking about associated channels. I do not know that Beyma TPL-150 driver. I have my reasons to suspect that it is a dreadful driver but I never had it.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-28-2012 Post does not mapped to Knowledge Tree
ayebee
Posts 13
Joined on 06-03-2005

Post #: 5
Post ID: 18786
Reply to: 18782
Why the low xo?
fiogf49gjkf0d
Why the need to cross the S3 so low? Crossing below 500Hz on a 260 horn seems to be pushing the limits a bit. What kind of upper bass solution are you planning? Regards, Anders
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