Rerurn to Romy the Cat's Site
In the Forum: Horn-Loaded Speakers
In the Thread: Macondo’s Midbass Project – the grown up time.
Post Subject: The back chamber predictionsPosted by Romy the Cat on: 7/22/2010
fiogf49gjkf0d
 Romy the Cat wrote: |
I do not have a final design of my back chamber. The image above is a concept that I deliver to my carpenter – we will go from there to see what we can do. I certainly would like do not overbuilt the back chamber. The notion of adjustability is very good but the back chamber most like will be adjusted ONLY once. Well, I do admit that I would like to be able to play with back chamber volume with respect to the plate loading of the 3C33C that will be driving the midbass driver. But in which extend I need to go I am not sure yet. A site visitor last night proposed to me his way to do it – with two set of slotted surfaces - it might be a good idea, I need to think about it. I will need to come up with a design this week. The walk-ins are
welcome…. |
|
I asked Jeffrey Jackson of Experience Music to help me with prediction of max sixe of my back chamber. I gave to him the T/S data for my driver and the horn dimensions.
FS: 47HZ
Re: 9.57 Ohm
Qms:9.173
Qts:0.304
Sd: 8.04^2m^2
Cms:2.35^4
Vas:7.42 cub.ft(212L)
dB 1W/1M: 99dB
Based upon his predictions I decided to stay with max sixe of back chamber of of 140 liters or 19 by 19 by 24 inches of I get near or above resonance of 40 Hz reactance-load driver. If after I load the drive into the horn I get low 30s resonance then I will go for the size of back chamber 19 by 19 by 16. The images below show the Jeffrey’s predictions.
Impedance and SPL at 75 liters (gray line) and 56 liters (black line).
Rerurn to Romy the Cat's Site