Gramophone Test No. 1: 100 Hz Exponential Horn vs. 150 Hz Tractrix Horn

A while ago, I made a small tractrix-ish horn from corrugated cardboard-technically, it isn’t actually quite a tractrix, as I used the perimeters of a round 150 Hz horn for the perimeters of the actual twelve-sided one, so the areas are slightly off; but at any rate, I thought it would be interesting to see how it compared to the exponential horn.
It isn’t quite a fair comparison, because the tractrix is supposed to have a 150 Hz cut-off and the exponential is supposed to be 100 Hz (although it actually seems to cut off closer to about 130 Hz), and because the lid can’t be closed with the tractrix horn; but it’s still interesting to hear the differences.
In person, the tractrix horn sounded brighter and clearer than the exponential, although sometimes to the point of being rather harsh; the exponential sounded much fuller, with noticeably stronger bass, but also seemed a little muffled at higher frequencies by comparison-unfortunately, it’s hard to say whether the tractrix’s brightness was due to the fact that it is a tractrix, or just that it’s a straight horn. I also used different soundboxes, but they were both late Orthophonic types, and generally sound fairly similar.
Both horns were tested using a Burmese Colour Needle and Victor record 22272-B, "Cryin' for the Carolines" by Waring's Pennsylvanians.

[@grahamrankin]

Most interesting comparison and for me--and over the wires---there is no contest. The Exponential horn wins every time and on every count. Better bass, clarity, presence and more natural treble---a great experience. The Tractrix, although good, seems not so magical via speakers but may be very different when in front of the horn. Just my opinion, of course, and very many thanks for the opportunity to listen. I know how much work goes into these projects so very well done and I look forward to further videos. I also think it would be a good idea if you are able to use the same soundbox as there are so many variables already aren't there and that would eliminate one of them.

[@e.q.b.gramophones7506]

I'm glad you found it interesting! On the whole, I would say that matches with the sound in person (to my ears, at least)--when I first made the tractrix horn a few years ago, I thought it sounded very good, but all I had to compare it to at the time were other corrugated cardboard horns and a small Orthophonic, so it may well have been better than them; but the homemade exponential does sound much fuller and richer.
In what way does the treble sound more natural on the exponential? Looking at the spectrum plots for the two (posted a couple days ago on the TMF--you may have seen them?), the treble on the tractrix extends up to 7000 or 8000 Hz, compared to 5000 for the exponential, although the response may be a little peakier--I would have expected it to be better than the exponential regarding treble, but it can seem rather harsh or thin by comparison; maybe the increased treble would sound fine with more bass as well, but the tractrix doesn't have enough bass to make it sound full and clear instead of harsh? Using the same soundbox would definitely be a good idea--also perhaps comparing both soundboxes on the same machine.

[@sc0or]

If I'd listen to gramophone I'd prefer to sacrifice 100Hz with tractrix in order to have a better clarity and a mid range. Cmon.. It sounds way better. I mean the first horn in the vid. Exponential sounds like a TYPICAL gramophone: narrow range with some sharp resonance.