Series tuned 6th order bandpass experiment

[Joe X]

I would very much appreciate if you posted input parameters for those, I have tried the parallel tuned version in Hornresp and while I didn't manage to get that perfectly flat top I think is close enough to confirm that changing the rear chamber tuning does not alter the port loading frequency of the front chamber (as before). Would it be fair to say you overlooked these results before making your test box?

[Triticum Agricolam]

No prob, here are the parallel and series tuned Hornresp inputs:

I'm not sure if I follow you as to which results I may have been overlooking before I built the box.

I don't expect the tuning of one chamber to affect to other with a parallel tuned box so I didn't do any testing with a parallel tuned system. Earlier I think I misunderstood you when you were posting the results of the parallel tuned box with different rear chamber tunings. I was thinking that was a series tuned box for some reason.

[Joe X]

Thanks for that (the series one needed the latest version of the software), no big deal, is just that it would seem to me like you found out that the loading frequencies were "linked" as you put it during measurements rather during the modeling that took place before building the box, again completely unimportant since it doesn't matter where you find out as long as you do, I guess there are many other useful measurements that can be done with it, here is the same comparison that you posted before through BBP:

Red: Series tuned 6th BP, Rear 3 net @ 24Hz, Front 2.4net @ 54Hz.

Yellow: Parallel tuned 6th BP, Rear 3 net @ 34Hz, Front 2.4net @ 54Hz.

[Triticum Agricolam]

OK, I follow you now. I did know that Hornresp was showing that the chamber tuning frequencies were linked before I built the box, I was just hoping that Hornresp was wrong :-)

I guess I should have know better since Hornresp has been very well developed, but my hope got the better of me.

The good news coming out of all of this is at least I know I can trust what Hornresp tells me.

[tboorn]

mmmmmm love me some 6th order knowledge. Ive always believed that in a 6th order series the inner chamber does effect the outer chambers tuning and vice versa. I have always just used paper and pencil when trying to do some rough designs for 6th orders, the formula i used for tuning incorporated both port lengths and port area in order to properly design. i really need/want to download a proper design program so i can input woofer parameters and really get s better view of potential outcomes.

[Triticum Agricolam]

mmmmmm love me some 6th order knowledge. Ive always believed that in a 6th order series the inner chamber does effect the outer chambers tuning and vice versa. I have always just used paper and pencil when trying to do some rough designs for 6th orders, the formula i used for tuning incorporated both port lengths and port area in order to properly design. i really need/want to download a proper design program so i can input woofer parameters and really get s better view of potential outcomes.

Here ya go, exactly what you are asking for: http://www.hornresp.net/

[Triticum Agricolam]

I was able to drag my BP6 test box out to get some half space acoustical measurements today. Here is what I got:

That's with 6.3 volts at 10 feet, so it should be pretty close to what a 1 watt/1 meter measurement would be.

I updated my Hornresp model to reflect what the port lengths were after I was done fiddling with them. Here is what it looks like:

I'd say that's pretty much spot on with what I actually got out of the box as far a frequency response goes. The actual box was a little more efficient that what Hornresp predicts. I've found that usually happens, but it could very easily be something in my test setup.

[Joe X]

Some happy numbers on the dB difference:

1W/1M:

6,1V/10 feet:

Using 6.3V and measuring about 8 inches short would mean 1 dB up:

Just throwing some numbers, the small error could be many other things like not using measured t/s parameters or something with the test.

Before cabin effects results seem pretty usable indeed.

[scooter99]

This was a nice stumble. I'm looking at doing a 6th for myself, and trying to understand it a bit more. This helps a lot. Thanks guys.

[Wasteland_Audio]

So here's a question, if you built a 6th order box and tuned both chambers to the same frequency, wouldn't it act similarly to a standard ported box but with more output?