DIY BMS 4550

Now, I am working on my "bigger" Tractrix Horn with the BMS 4550. The BMS 4550 is a superb compression driver. Only the price is already a little high. The frequency response is 500 Hz to 20 Khz. They Claim 113 dB 1W / 1m. I choose this model, because I do not want an additional tweeter. I will use a bass / midrange speaker with this horn. But I do not know what bass / midrange I will use. Here some pictures of the BMS compression driver.




My new tractrix horn is a 2" horn, so I bought a Beyma adaptor. The adaptor is from 1" to 2". It is made from good aluminium. For the BMS driver, I have to drill 2 new holes, that the BMS fits.




And here the mounted adaptor and the BMS. Everything is fitting nicely. I am using stainless srews, they are non magnetic.




And here the wooden tractrix hor. My German friend builded for me. The wood is "Ahorn", a German wood. The wood looks very nice and the finish is excellent. For scale reason, I put the 13 cm tractrix horn with the big horn. The big horn is close to 40 cm in diameter.




Here the fully assembled horn. You have to take care, that the adaptor between driver and horn is absolutely aligned.




Than I start to build a easy stand for the horn, for a quick listening.I put the horn on top of my green cones, maybe a little to high, but for testing okay. First I listen to Billie Holiday. I music image was very clear and detailed, not to bright. The trumpet was unbelievable. Of course, I have to build a better stand, use better cables and better caps. But the result so far is better than I thought. Now I have to look for a better bass / midrange speaker.




I have made two new stands for the horns. Now the horns are adjustable in height and angle. I listen to to new horns with my Hemps yesterday. The set up is more difficult, than with the small horns. But the sound is really fascinating, escpecially female voices and trumpets. I have to build a better network, that the horn goes deeper. But so far, I am happy with the result.




I listen to my Hornspeakers with the EL34 SE Mono Blocks. I remember, that Jamie liked these amps very much, as he has heared this amps at Moom Sabai. I also was atonished yesterday, how good they sounded. The sound stage was very detailed. I listen to Sarah Vaughan. I will post later some details about this amp.



I have tested an extra horntweeter to the existing horn. My conclusion is, that too many speakers are difficult to setup. The best is, keep it easy. The big horn with the Hemp sound very good. Maybe, I also will build a 12" bass horn for the big BMS horn.