Hi All,
I've been considering the build of a Sonido SWR-300 in Onken cabinet. It seems perfectly suited, so that's not the issue. I'm having difficulties understanding the "Rg" parameter. It is said to be the "total components resistance (xover coil, terminal, wire, amplifier, etc.)". Since there won't be a crossover, this leaves the resistance of the amplifier. This would mean, if my logic holds up, that I'd need to either build a new enclosure every time I connect another amplifier, or I'd need to build a flexible enclosure (huge - filled with sandbags to change volume for example).
Am I correct? Or am I over-analyzing this, in which case the question would be at what level should I put Rg? Would it be 0.1 Ohm, or 3 Ohm or more?
Any help would be appreciated.
I've been considering the build of a Sonido SWR-300 in Onken cabinet. It seems perfectly suited, so that's not the issue. I'm having difficulties understanding the "Rg" parameter. It is said to be the "total components resistance (xover coil, terminal, wire, amplifier, etc.)". Since there won't be a crossover, this leaves the resistance of the amplifier. This would mean, if my logic holds up, that I'd need to either build a new enclosure every time I connect another amplifier, or I'd need to build a flexible enclosure (huge - filled with sandbags to change volume for example).
Am I correct? Or am I over-analyzing this, in which case the question would be at what level should I put Rg? Would it be 0.1 Ohm, or 3 Ohm or more?
Any help would be appreciated.
To a point, but if we're talking amplifier output Z or a voltage source amplifier with some series R in the circuit (wire, binding posts &c., which they all have unless you've got a superconductor handy 
) that would apply to any and all enclosures, so this is not exclusive to an Onken by any means. An Onken is just a descendent of the trad. bass reflex with its massive vent system.
Which is a long-winded way of saying 'yes and no, but that applies to everything anyway'. In an ideal world, since a loudspeaker is just one part of a system that includes the electrical properties of the wire and the driving amplifier, you design it to account for those. If you aren't planning on wild differences in amplifier output Z, then I wouldn't worry too much: just account for the intended amplifier output impedance and any series R, and leave at that. If you want to alternate between amplifiers that have a modest difference in their output impedances, then best bet is to go with whatever option yields the largest box & if necessary add some series R for the amplifier with the lower output Z to maintain alignment consistency.
) that would apply to any and all enclosures, so this is not exclusive to an Onken by any means. An Onken is just a descendent of the trad. bass reflex with its massive vent system. Which is a long-winded way of saying 'yes and no, but that applies to everything anyway'. In an ideal world, since a loudspeaker is just one part of a system that includes the electrical properties of the wire and the driving amplifier, you design it to account for those. If you aren't planning on wild differences in amplifier output Z, then I wouldn't worry too much: just account for the intended amplifier output impedance and any series R, and leave at that. If you want to alternate between amplifiers that have a modest difference in their output impedances, then best bet is to go with whatever option yields the largest box & if necessary add some series R for the amplifier with the lower output Z to maintain alignment consistency.
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Thanks!
Thanks Scott, that makes sense, if the build happens it'd be quite a construction to get wrong!
Can't believe it's been 10 years since the last build you played a big part in. Then it was the Nagaoka style Lowther design, 2 meters tall.
I'll be home late June for a few months, with my little 4 year old running around it may take a while to get this project off the ground.
Thanks Again!
Thanks Scott, that makes sense, if the build happens it'd be quite a construction to get wrong!
Can't believe it's been 10 years since the last build you played a big part in. Then it was the Nagaoka style Lowther design, 2 meters tall.
I'll be home late June for a few months, with my little 4 year old running around it may take a while to get this project off the ground.
Thanks Again!
FWIW, the pioneers used 0.5 ohm as the default for just speaker wiring attached to a low output impedance amp, which doesn't audibly change most reflex alignments. Tube SETs and especially matching impedance amps OTOH can double Qts, which until Vas is quite large is the dominant spec WRT net cab volume: Vb = 20*Vas*Qts'^3.3
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
Output Impedance
Thanks GM. It's good to have your input, in this case it further completes the picture. I've come to the attached results; a very acceptable 230 liters or about 8.1 cubic feet. The ports will add a bit of attractive bulk to the sides, so nothing to worry about.
I hope I can now find some time this summer when I'm at home, it should be a fun, relatively inexpensive, project. Thanks again GM & Scott.
Thanks GM. It's good to have your input, in this case it further completes the picture. I've come to the attached results; a very acceptable 230 liters or about 8.1 cubic feet. The ports will add a bit of attractive bulk to the sides, so nothing to worry about.
I hope I can now find some time this summer when I'm at home, it should be a fun, relatively inexpensive, project. Thanks again GM & Scott.
You're welcome!
Yeah, its vent arrays make for a nice industrial design.
Is the Excel calculator available? It's got more features than mine.
GM
Calculator
It's a combined spreadsheet I'm working on. I may eventually include a BiB section also. As it is it'll give you a nice overview of a driver's suitability as well as a few toys to play with (frequency response, excursion, power response). You're welcome to it, I'm open to feedback as well. Unfortunately I can't attach an Excel file apparently
It's a combined spreadsheet I'm working on. I may eventually include a BiB section also. As it is it'll give you a nice overview of a driver's suitability as well as a few toys to play with (frequency response, excursion, power response). You're welcome to it, I'm open to feedback as well. Unfortunately I can't attach an Excel file apparently
Ah! Thanks!
IIRC, a long time ago someone mentioned that the .xls can be saved with a different extension, then converted back at the other end, though don't recall whether any of the acceptable ones will work or ???
Unfortunately I don't currently have Excel installed, so others will have to chime in.
GM
IIRC, a long time ago someone mentioned that the .xls can be saved with a different extension, then converted back at the other end, though don't recall whether any of the acceptable ones will work or ???
Unfortunately I don't currently have Excel installed, so others will have to chime in.
GM
Calculator Screenshots
Here's what all output looks like. It's a handy little tool, nothing extraordinary, just easy to use and light on memory and only 128 Kb in size or so. If we can figure out how to post Excel files I'll be more than happy to share it.
In a way we're still on topic... in a way...
Here's what all output looks like. It's a handy little tool, nothing extraordinary, just easy to use and light on memory and only 128 Kb in size or so. If we can figure out how to post Excel files I'll be more than happy to share it.
In a way we're still on topic... in a way...
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