Some of you have already seen my old posts about the 2 pair of concrete midbass horn a friend and I built a few years ago. > >

Now I just wanted to share what has happened to those beauties since the last post.

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My friend, Per, was (as always) quick to finalize his installation. These horns are now a part of his very nice system. The system features: A pair of 16 Hz concrete bass horns extending under the floor of the listening room and with their mouths located behind the listening sofa; The concrete midbass 100Hz horns as described earlier; Tractrix 350 Hz horns and a pair of pleated tweeters on top. The drivers are: JBL 2220J; TAD 1201;TAD 4001; Beyma TPL-150H.

Here are a few pictures of the system. See the bass horn mouth and Per painting the horns.

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Being a great DIY:er Per has built the speakers, amplifiers, other electronics and most of the house.

Overall the system sounds very good. Great dynamics with a nice tone and good coherence. The best indoor system I have heard. > >

Bass response is by far the best I have heard. The 16Hz horns can produce some impressive acoustical power. The sound is spectacular: effortless and just right!

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Now to the second pair of the concrete midbass horns: Mine are still placed in the garden! > >

A couple of years ago I knocked down an old carport and a couple old sheds. This gave me a possibility to set up a nice barbeque sound system.

A nice day with no wind! System is playing beautifully and the barbeque is ready to be ignited. That’s how life should be!

The first season the midbass horns were equipped with phase plugs and L.Cao t="on">8 inch fullrange drivers. The L.Cao worked ok. I now use these in my garage in t="on">85 liters vented cabinets.

The next season 18Sound 8M400 replaced the L.Cao in the horns. These drivers have much higher efficiency and sounds strong and dynamic in the horns. Surprisingly sweet tone for a pair of PA mids.

A few different tweeters have been used but now I use a pair of Altec 802-D on 350 Hz horns. They work ok but chokes when I play too loud.

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Listening to this system outdoors has been nice, interesting, educational and chocking. Now I understand the importance of the room. The barbeque system has a room of the right size. Anything smaller will degrade the performance. The lack of reflecting surfaces is a nice feature of this room. > >

Now dynamics, instrument placement and sound stage sounds right for the first time. I didn’t think this was possible to reproduce anything like this with a pair of speakers. You can also play at the right volume without the nastiness you usually gets indoors.

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The Bad system features: crap electronics; many meters of the cheapest speaker cables; limited bandwidth; no real crossover, only a tweeter cap; far from flat frequency response; weather depending.

The Good system features: life like reproduction of music at realistic playback levels; possibility to effortless transform my garden to a jazz club, church, concert hall and so on. They are also a nice thing to have in the garden and appreciated by the cats.

If you have the chance and understanding neighbours, try it for yourself. > >

Note the free space between the barbeque horns! Possible position for a 35-40 Hz horn that might be built.

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Happy New Year! Ulf

Hi Paul,

The L.Cao are quite nice fullrange drivers at a reasonable price. Compared to Lowther EX the L.Cao lacks some dynamics but have a better tone and are more homogeneous. I am no fan of whizzer cones. To use it as a midrange should most likely work fine.

Best Regards: Ulf

Hi Romy,

Sunfire? No! Who would add a Sunfire to this system? The black box in the pictures a power amplifier for the midbass horn.

A second MF could be interesting. I will see if we can do some test set up of this. Per has the space for it, I don't. See the image of my room and the very difficult conditions I have.

I use GPA 515-16G, Radian 950PB-16 and TPL-150H. I had a pair of vented subs but I got rid of them a month ago. I was not able to stand them any more. Now I will build a pair of Tapped Horns and see if they can be used. Anyway the Altec (copy) cabinets sound better laying down, at least in this room.

Electronics, crossover and so on: me and Per use similar stuff. All DIY minimalistic (discrete, minimize number of gain stages, no feedback) approach. We have a friend who is a skilled and creative designer of electronics and we are lucky to be allowed to use (but not share) his designs. The latest is a new amplifier design. Per use this design for all his amplifiers, I use them for mid and tweeters so far but will be building the bass amplifiers on this circuit as well.

Walls, floor, ceiling! Yes, all these are bad things! As noted with the barbeque system a free space is so much better. You can easily see the problems I have indoors!

The TPL is nice! Actually the first tweeter I have heard that I can say is good. All others I have heard add some HF in combination with hissing, sharp metal or broken glass. I have also heard a few ribbon tweeters with a nice tone that not was possible to integrate with a mid horn. We both cross it at 7kHz, 6dB and that works well.

About the bass horns: I had the same concern before I heard them. Per's set up is now time aligned. The bass horns sort of fill the whole room. I can't say that I think they need any distance to bloom. In the listening position it is quite easy to forget the bass horns. The punch comes from the midbass horns. Walking around in the room the bass sounds a bit different, but I think it has more to do with room modes. They can produce some serious acoustical power and hearing that with the quality and LF response they have is spectacular. This is the only system I have heard that has good bass response. Nothing strange really, same principle as midbass and mid horns, but the size is difficult to fit in a home.

Best Regards: Ulf