GoodSoundClub - Romy the Cat's Audio Site

Horn-Loaded Speakers
Topic: DIY Firefly Horns

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Posted by Romy the Cat on 03-24-2011

I have no idea what he is and what he is looking for. He declares himself as “just an average guy in an average basement shop building hi-fi audio horn speakers from wood”. I do not even know in what country his leaves, not that it is important. He has a site and a blog:

http://sites.google.com/site/diyfirefly/

http://diyfirefly.blogspot.com/2010/09/horns-are-up.html

Anyhow, he looks like recently made a new installation.

Let see what it is. The playback has 38 Hz tapped horn, 100 Hz Multi-Sided Conical Exponential Horns with unknown drivers, the 320 Hz Round Tractrix Horns with JBL 2446 and some kind of tweeters. It looks an attempt was make to time-alight then in frame – a good sign. The author is concentrated on the wood crafting and provides no information about sound of the thing, crossovering and anything else. The horns are not positioned properly; most likely they are not even connected and juts too fresh.

From what I see the MF horn might be too high. It is hard to judge as it is not known what the eyes level on the picture is. The Midbass looks like as good idea, but I would go for not even amount of sides. The back chamber look like too big but it might be made this way intentionally in order to be a base for the rest of the frame. It would be very interesting to hear how the tapped horn sound – never heard them….

The Cat

Posted by green heron on 04-08-2011

As the builder behind these horns, I can answer some of your questions. It's true, I was primarily focused on the woodworking/building side, and now I'm experimenting with amplification and crossovers. I can't speak authoritatively on those subjects, so I didn't focus on that part on my website.
That picture that you posted was just after I built the horns, but prior to experimenting on the amplification/crossover side. I ended up moving the horns further apart and away from the corner of the room. Then I placed the tapped horns toward the center to reduce the boundary gain I was hearing. I haven't had enough experience with a variety of tapped horns to form an opinion of the concept. But I can say that I'm looking to replace the 38 Hz tapped horns and try something more efficient--probably 25 Hz tapped horns at around the same efficiency as my midbass horns (101 db) if I can get them to reach high enough to mate well with my 100 Hz midbass horns, which is the challenge with tapped horns (they have a very narrow range). The throats of the 320 Hz tractrix horns are 34" tall, right at ear level. All drivers were time aligned with a scope. I added a passive first-order crossover between the tractrix midrange horn and tweeters (JBL 2402) and that set-up is powered by a 45 amp. I'm happy with my results midrange on up at the moment, but I'd like more slam from the midbass horns. The backchamber may be a bit too large, so I'm planning to experiment with the cabinet volume. Do you have any suggestions to tell what the ideal cabinet volume is and what the typical sound characteristics that indicate if a backchamber is too large?

Posted by Romy the Cat on 04-09-2011

green heron wrote:
I'm happy with my results midrange on up at the moment, but I'd like more slam from the midbass horns. The backchamber may be a bit too large, so I'm planning to experiment with the cabinet volume. Do you have any suggestions to tell what the ideal cabinet volume is and what the typical sound characteristics that indicate if a backchamber is too large?

Yes, you will have more “slam” from the midbass horns if you tune your back chamber. When your backchamber is too large the lower knee of your midbass sound very light, you get more extension and bass accent with back chamber properly tuned. I had guidance how to do it.

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=2991

My article was written for as your midbass that has slow beginning of the opening. Your horn is conical and I do not know how they behave. Conical horns are reportedly very unpredictable and you woeful never know how they behave. So, you need to drive your Fs up and down to see how your conical horns will response to it.

The Cat

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