Reverse Polarity?

I know it's a lot already but... Just to be extra clear. When he says this. 

"Listening to a single sine wave will not reveal this as is proven time and again by attendants of my seminar because we're not exposed to neighboring frequencies. Should you decide to align by ear then at least use a signal that exposes you to all frequencies of interest like Michael Bink Knowles Audio Test's warbles."

The reason the neighbouring frequencies are important is, an incorrect CYCLE alignment will be exposed by the lower or higher frequency not aligning. However, if the cycle alignment was correct and you used the sine wave method, the neighbouring frequencies will be intime. You'd have the same result as the other method. If your speakers are close together one isn't going to add a delay time big enough to hit the 1st cycle inphase, out of time, never mind the 2nd. The main issue we'd hit is more like 50/50 over the polarity choice.

When he says

"As long as both speakers are producing the same signal there are an infinite amount of possibilities for being in phase (either with or without polarity inversion) and not on time. Whereas there's only one possible outcome where both speakers are in phase and on time"

He is seriously exaggerating the "infinite amount of possibilities" to suit his argument. Although he is correct, no one would move to those "infinite" possibilities of alignment. The 'tape measure and basic understanding of sound' will give you a ball park figure with in the range of 1 cycle. You'd only get 1 cancellation to set it to before moving out of that range... Well 2 if you include getting the polarity wrong.

On concert systems, line arrays, it 's a different story but we're talking about simple stacks. The wave length of the frequency is too long to warrant an engineer putting in the wrong time delay, to land in the next cycle, where the next null would be.

I hope that makes sense. It's took a lot of thought to try express it.

Just to be double clear... If using the sine wave method, if you are on 0 cycle and have a null with incorrect polarity, when you flip polarity you will be on

"Whereas there's only one possible outcome where both speakers are in phase and on time"

I hope that helps. Any further discussion is welcomed. I appreciate the graphs, thank you.




Edited by mitchiemasha - 18 October 2017 at 11:10pm

Option 6. Don't use the reflex and horns together. It's always best to not mix different types of subs and now you know why.

The ports on the B400s may have just been a cheeky way of getting a little more lowend out of them.. or perhaps a way to cool the drivers a little better, but in both cases it's doubtful there would be enough of a difference over sealed chambers to justify the increased risk of destroying the drivers by driving them below tuning. That right there is another reason not to run these from the same output as the reflex bins, they may work fine at moderate power levels but at war volume you may just destroy the drivers if you feed them a 40hz tone.


Edited by Conanski - 19 October 2017 at 5:17am

AJ113 wrote: Well no, not really. I won't know either way until I actually try it. I mean to be fair my question was not whether to go ahead or not, but how best to deal with the manufacturer's recommendation. The manufacturers themselves don't say "don't do it" so I don't see why it shouldn't at least be tried.

What ever you do. To you it will sound Ok. But it will be wrong. It's impossible to do an A/B comparison to know which actually sounds better but you will believe and convince your self of such!

Personally i'd of simply done as the manual said. Flip the polarity. Then with each passing week, as i learned i would of tried new things correcting for my (in this case your) mistakes. Don't be that fool that 'thinks' it right.

I've been forced my life to run a mismash of systems but i never once pretended to myself. You're not going to miraculously fall onto a really good match up or be able to correct all it's errors. The compromises at the end of the day are yours to make.

AJ113 wrote: mitchiemasha wrote: ...To you it will sound Ok... If it sounds ok it's not 'wrong'. It's only wrong when it doesn't sound ok. I trust my own judgement in that respect.

I was worried that you would think that way... Although it's way to hard for me to explain why everything about what just wrote IS wrong.

The main problem is you have no way of knowing if it's the best it can be. It's impossible to A/B. Perhaps 1 day you'll understand.

If it sounds OK it'll do... but it is wrong! Some of us ain't happy with it'll do. I was always never happy with the sound, even when everyone else loved it. I have a friend who thinks like you! It's took me many years to convince him of how bad he did things. He's slowly starting to learn. 

mitchiemasha wrote: ...The main problem is you have no way of knowing if it's the best it can be...It's impossible to A/B.

Ok but that doesn't apply soleley to me, it applies to everybody.

mitchiemasha wrote: [quote]I was always never happy with the sound, even when everyone else loved it.

That suggests it's you who may learn one day. If everyone in the venue loves the sound, it's job done.

Answer to 1 is because it assumes you've read the rest of the handbook and applied the active crossovers they recommend.

Answer to 2 probably program material and level id guess.

Answer to 3 is if you're happy then good for you. Carry on as is. If you want to learn and improve then dig deeper into the theory.