Rockville M-4 At .5 ohm (no joke)

[ShadeTreeMechanic]

Yes you are right. Thanks everyone for your input. On a sealed box designed with a Q of .7 for flat response if a driver is chosen with some value for Fs then that will give the flattest response that peaks at some frequency. Right now my HDS315s smash the lows with a port resonant frequency of 34hz. This is because there is a big response at that frequency because the box Q is 1. My first try was at .7 as always but because The Qt of the woofer is .829, it gave me a negative number for box volume. A Q of 1 gave me a box of 4.4 cubic feet and a box resonant frequency of 43hz. Then the port at 34hz with about a 5db bump. So if i picked a sub that had a lower Qt so i could use a box Q of .7 then it would smash the same lows? No but it wouldn't have a big bump so would be more even with the upper bass thus making upper bass comparatively louder. Duplicate this setup to get as loud as you want.

Whoa, now hold on a second. You realize Qtc doesn't really apply to ported boxes.

You got 8"s crammed in there too? What frequencies are you sending to those?

To each there own, but simplicity is the ultimate sophistication (IMHO).

like how the old school sq guys would compete with 2 tweeters and a single 10"?

Yeah, sometimes less is more. Sometimes more is more fun.

[MADVIBES]

I would like to address the percieved notion that you can plan a full range system with careful planning and equipment selection. I know for a fact that you can do this with only one sub involved, I also know its impossible to do with output levels nearing 150db, there just are not any high power high excursion drivers that can give you the upper register and the low of the lows in a flat response. I think his approach here is truly novel and the only way to do this. well let me step back and say high output can be acheived in possibly a multi sealed subwoofer setup. but even then the box would have to be huge to yield strong output at 20hz.

bravo to you shade! You could also make tuning your subs easier if you have a decent db meter and used it and an eq to level match your bass freq's

[ShadeTreeMechanic]

I would like to address the percieved notion that you can plan a full range system with careful planning and equipment selection. I know for a fact that you can do this with only one sub involved, I also know its impossible to do with output levels nearing 150db, there just are not any high power high excursion drivers that can give you the upper register and the low of the lows in a flat response. I think his approach here is truly novel and the only way to do this. well let me step back and say high output can be acheived in possibly a multi sealed subwoofer setup. but even then the box would have to be huge to yield strong output at 20hz.

bravo to you shade! You could also make tuning your subs easier if you have a decent db meter and used it and an eq to level match your bass freq's

Thanks Madvibes, Thanks for the input. So now i only feel half crazy instead of completely crazy. I was thinking about trying to find a fairly priced RTA. If i used a db meter then i could use a spectrum sweep track to find the bumps and dips in response? Would a db meter be able to read the frequency too?

[MADVIBES]

a db meter could if it was set up for that. if you got a hand held db meter say a digital one from radio shack, you could get a subwoofer test cd and go through the tone section one by one and meter your system at la set output and change the tracks and sort of build your own graph using graphing paper that would be a fairly simple way to get an idea of your bass response how ever those meters usually dont work above 130db so you would be limited on your high output testing and that was the whole point of the bi amp'd system.

Term lab can do what you need, pricey for sure. I am not familiar with the spl labs mic and app but that might be promising, i will let someone who has experience with that product answer that question.

[Triticum Agricolam]

For a reasonably priced RTA a setup all you need is a calibrated mic, a laptop, and your choice of free RTA software (I use Room EQ Wizard and HolmImpulse). Here is a good example of a calibrated mic:

https://www.parts-express.com/dayton-audio-umm-6-usb-measurement-microphone--390-808

You won't be able to measure your max dB with that mic, but you will be able to measure your frequency response.

[MADVIBES]

he needs to be able to do a high output rta test. thats going to be really hard to find other than a term lab or possibly an old audio control rta with a high spl mic

[ShadeTreeMechanic]

Thanks Guys! The wheels in my head are turning.Maybe there would be a way to attenuate the mic signal? Or is it the physical limitations of the mic.

[MADVIBES]

if its not a mic that is designed to handle high pressure you will overcompress the diaphram and all the reading will be grossly inaccurate

[Triticum Agricolam]

Its the physical limitation of the mic. If you want to measure at full power, you are going to need a Termlab.

The Dayton mic would still let you measure the frequency response and set the levels on your amps so the output matches between your different drivers.

[ShadeTreeMechanic]

Its the physical limitation of the mic. If you want to measure at full power, you are going to need a Termlab.

The Dayton mic would still let you measure the frequency response and set the levels on your amps so the output matches between your different drivers.

So as long as the different amp gains are fairly linear or curve the same way then it wont be too bad when it is at max. This is where staggering the amps size for each section becomes problematic. The next problem is when one amp maxes out before the other. That will be the highest system output while staying balanced. Right?