Rerurn to Romy the Cat's Site


In the Forum: Horn-Loaded Speakers
In the Thread: Deep End DIY - Australian take one Macondo.
Post Subject: The pipes, the pipes are ringing...Posted by anthony on: 7/4/2017
 Jorge wrote:
Hello Anthony,
I did experiment with metal tubes for bass in a sealed configuration as you are planning. The weight of them, even made out of thinner than you would like steel, is prohibitive.  If you make them out of aluminum pipe, then it could be better, but still pretty heavy.  The stack will probably be unstable and shakey.
Do not try to place them one further than the other, or not perfectly aligned,  the bass will distort terribly, cancellations will cause a mess of the sound, remember they will be playing the exact same frequency. (I did that and learned from the experience)
 


Hi Jorge,

Thanks so much for chiming in.  It is nice to hear from someone that has been where I am going with this.

For this project I am not letting the weight of an object concern me.  I have a very strong floor in my room and with some careful forethought I should be able to drag heavy items around by myself (or perhaps with a friend if really required).  To date I have made 5 pipes, each 263mm diameter (10" or thereabouts) with 4.8mm wall thickness and 10mm welded endplates.  They feel like they are about 30kg each which is very manageable, and by the time I damp them and install the driver perhaps they will reach 40kg each.  I feel that this is manageable, especially because I have limited by the size of things that I can get into my room and I can carry one cannon at a time into my room.

I did wonder a little about cancellations and will experiment with it when the time comes, but thanks for sharing your experience.

 Jorge wrote:

Of course they look much better than the boxes with the added benefit of difussion of sound waves hitting on it, against the reflection from a flat side panel of a box, so there are a lot of considerations you must make.
The bass modules I am using now are actually a form of concentric tapped horns using a long excursion 8 inch woofer servocontrolled by a powerfull class D amp.  These are a redesign from the original, longer, passive bass modules which sported a 6.5 inch woofer.   I am using one per side now. 


I am not sure that they look much better, they might by the end of it, but the construction methods agree with my tendencies and are in my comfort zone.  The diffusion angle is quite a valid one I would think that in the back of my mind this was one of the reasons that I have decided to investigate the pipes design.  They should diffuse "in phase" as well which is a bonus.

I have had the 5 undamped pipes sitting up in the corner of my room and have had to take them out because when I play very loud music the pipes are induced to ringing.  They store and release that energy over time and add a metallic tinge to the sound.  They are now downstairs until I can get them damped.

 Jorge wrote:
Hello Anthony,
The bass modules I am using now are actually a form of concentric tapped horns using a long excursion 8 inch woofer servocontrolled by a powerfull class D amp.  These are a redesign from the original, longer, passive bass modules which sported a 6.5 inch woofer.   I am using one per side now. 


They do look a nice design.  My one overriding ambition with the Bass Cannons is to have a bass channel that I can drive with a full 6C33C SET amp. My transformer winder has prepared an OPT that will drive 1R to 9W at 1% distortion and 2R to 17W.  Each stack of pipes will have a box at the back where I can experiment with parallel and serial driver connections.  If I can get this all to work I think that I will have a truly unique bass channel if only it can be coaxed into good sound.

Cheers,

Anthony

Rerurn to Romy the Cat's Site