GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Horn-Loaded Speakers
In the Thread: S3 on tractrix 260 graph.

Post Subject: OK let's have a dedicated S3 threadPosted by gordan on: 11/28/2012

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...

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