Stand-mounted vs. Floorstanding

[QMuse]

I'm not.

You do realise that the vast majority of speakers have delays between woofer and tweeter and yet they can still sum at the xo and sound fine.

No, they don't - at XO point woofer and tweeter have exactly the same angle otherwise you won't get linear FR as they will not sum up correctly.

Let's do some calculations:

So, only 5ms of delay in IR gets you 144 deg of phase shift, shich certainly is not something you should ignore.

Let's now see how it would look. Here is phase response of my mains. Blue line is a typical phase response of the sub with properly aligned phase and red is what you get with sub that is 5ms delayed. As a result sumation at XO point at 80Hz would be very chopy and there will be a huge jump in phase and also in a GD response if sub is left that way. But GD is the least of your worries as summation will be screwed and that will spoil frequency response. as sub is 5ms late you can also say good bye to the punchy bass due to "echo" effect.

 

[March Audio]

No, they don't - at XO point woofer and tweeter have exactly the same angle otherwise you won't get linear FR as they will not sum up correctly.

Let's do some calculations:

View attachment 55147

So, only 5ms of delay in IR gets you 144 deg of phase shift, shich certainly is not something you should ignore.

Let's now see how it would look. Here is phase response of my mains. Blue line is a typical phase response of the sub with properly aligned phase and red is what you get with sub that is 5ms delayed. As a result sumation at XO point at 80Hz would be very chopy and there will be a huge jump in phase and also in a GD response if sub is left that way. But GD is the least of your worries as summation will be screwed and that will spoil frequency response. as sub is 5ms late you can also say good bye to the punchy bass due to "echo" effect.

View attachment 55148

Can you stop switching terminology.

Why are you now talking phase as opposed to time?

This is an absolutely typical speaker step response. The woofer is not in time with the tweeter. Yet the world still revolves and it sounds fine.

There might be typically 0.4 ms delay between woofer and tweeter which at 2khz is 288 deg difference.

An lr4 xo will put the signal 1 cycle (360 deg) out of time but that's still in phase and sums correctly.

You are still ignoring the point that your mains are also moving phase at low frequencies. Possibly the 4th time I mentioned it.

It will not cause an echo.

 

[QMuse]

Can you stop switching terminology.

Why are you now talking phase as opposed to time?

O come on - you're an engineer, you should know better than that, phase and time are the same thing with given wave speed and frequency!

Not to mention that is something you learn in gym - maybe you should look at wiki and remnd yourself of circular motion formulas.

This is an absolutely typical speaker step response. The woofer is not in time with the tweeter. Yet the world still revolves and it sounds fine.

View attachment 55149

An lr4 xo will put the signal 1 cycle out of time but that's still in phase and sums correctly.

You are still ignoring the point that your mains are also moving phase at low frequencies. Possibly the 4th time I mentioned it.

It will not cause an echo.

You can equalise phase of woofer and tweeter only at one frequency and that is done at (and in proximity of) XO point. For sub and woofer you should do exactly the same thing.

And of course there will be "echo" if sub is playing 80Hz tone 5ms after the woofer.

No offense, but I really thik you should do some more reading before continuing this discussion.

 

[March Audio]

I'm fine with the relationships thanks, I just don't like shifting goalposts.

Integration is not just dependant on the subs delay. It will be relative to the mains. Also talking about "x" ms delay doesn't tell you about audibility.

No there won't be an echo.

 

[QMuse]

I'm fine with the relationships thanks, I just don't like shifting goalposts.

I'm not shifting anything, I was always talking about 5ms delay between impulse responses (not GD) and phase and time are defintiely directly related.

 

[March Audio]

I'm not shifting anything, I was always talking about 5ms delay between impulse responses (not GD) and phase and time are defintiely directly related.

You never stated your conditions.

I have never stated anything to the contrary, but time delay and phase are not the same thing.

Ok, so explain why speakers that are not time aligned between woofer and tweeter (the majority) sound (generalising) OK?

My example above is more out of phase than your example.

Also think about your ability to discern the timing of low frequency signals.

 

[QMuse]

You never stated your conditions

Or maybe you didn't read carefully my posts?

I have never stated anything to the contrary, but time delay and phase are not strictly the same thing.

Here you go again : with circular movement time and phase are DIRECTLY related via frequency and speed of the wave. It is absolutely irrelevant which one you want to use as they are interchangeable.

Ok, so explain why speakers that are not time aligned between woofer and tweeter (the majority) sound (generalising) OK?

This one is an interesting question and from what I have seen many folks are not clear with it. Crossover specialist would do that much better but let me give it a try.

First of all, with decently sounding 2-way speakers woofer and tweeter are absolutely phase aligned at XO point. Let's see how it works with my speakers:

Blue line is phase response of my uncorrected speaker. XO is at 1800Hz, LR4 24db/octave. If I didn't tell you that you never would have guessed as phase response is very smooth in that region which means at 1800Hz they are phase aligned. And they should be otherwise there would be a horror in frequency response around XO point.

Let's have a look at step response, again blue is uncorrected. It looks typical, doesn't it?

Red lines are phase and step response after phase of the passive LR4 crossover at 1800Hz has been corrected using this phase filter:

Here's another view of the same filter so you get a better idea what it does:

As a conclusion: although woofer and tweeter are phase aligned at the XO point passive LR4 XO shifts the filter all over the audible range and that is what you are seeing while looking at uncorrected step response. But if you correct it you will end up with a very decent phase and step response. That of course still depends on the quality of the drivers of your speaker as junk drivers/speakers cannot be EQ-ed whatever you do.

Different types of crossovers will of course have different phase signatures but all of the standard ones can be corrected and that is what automatic EQ tools like Acourate, Dirac etc are doing. When they mention they correct things in time domain they first correct phase response of passive XO and then they try to linearize phase response to get excess phase (difference between actaul and minimum phase response) as close to 0 while avoiding pre-ringing with step response as that causes audible artifacts which are much worse than high GD.

And that's about it, what can fit on one page, hope it helps!

 

[QMuse]

Btw, when woofer and tweeter are NOT phase aligned in the XO region there will be a visible dip in the anechoic frequency response. Not every dip at XO is due to phase-misalignement but phase mis-alignement will always cause a dip.

 

[Karu]

My sub delay was 1.4ms. I corrected this. Is phase different concept and can it be corrected inside Roon/MiniDSP? On sub Delay/phase is a single knob...

 

[March Audio]

Or maybe you didn't read carefully my posts?



Here you go again : with circular movement time and phase are DIRECTLY related via frequency and speed of the wave. It is absolutely irrelevant which one you want to use as they are interchangeable.



s!

Time delay and phase are absolutely not interchangeable in this context. You haven't grasped the difference. Time is ×not× phase.

Two signals can be 1 cycle (360 deg) out of time and will sum perfectly in an XO. This is exactly what an lr4 does.

 

[QMuse]

My sub delay was 1.4ms. I corrected this. Is phase different concept and can it be corrected inside Roon/MiniDSP? On sub Delay/phase is a single knob...

At any given frequency time delay can be calculated to a phase shift and vice versa. On this page you will find explanation and calculator to do that.

I don't think you can do that with Roon/MiniDSp as they are using IIR filters which correct only frequency response, not phase response.

Time delay of 1.4ms equals 40deg at 80Hz and that is not something that would cause audible issues, but of course, if you have means to correct it than you should absolutely do it.

 

[QMuse]

Time delay and phase are absolutely not interchangeable in this context.

Two signals can be 1 cycle (360 deg) out of time and will sum perfectly in an XO.

Imagine a situation where you have 1 second of time delay between sub woofer and mains woofeer at 100Hz. While they are in phase (from 360deg circle point of view) you will not have phase cancelations, but you will have sub playing a 100Hz tone a whole second after the mains played it. How do you think that would sound? Punchy?

 

[March Audio]

Imagine a situation where you have 1 second of time delay between sub woofer and mains woofeer at 100Hz. While they are in phase (from 360deg circle point of view) you will not have phase cancelations, but you will have sub playing a 100Hz tone a whole second after the mains played it. How do you think that would sound? Punchy?

Why have you felt the need to exaggerate the scenereo to a ridulous level if you beleive your original point is valid?

Just because you might hear a difference a 1 second doesn't mean you will hear a difference at 0.005 seconds.

A 20hz sine wave takes 10 times that period to complete just one cycle.

 

[QMuse]

I never said time and phase are the same thing, I said they are DIRECTLY related. For the drivers to be "in phase" you to need to check they are actually time aligned as 40 deg and 400deg at some frequency are looking exactly the same on phase graph but they are NOT time aligned.

 

[March Audio]

I never said time and phase are the same thing, I said they are DIRECTLY related. For the drivers to be "in phase" you to need to check they are actually time aligned as 40 deg and 400deg at some frequency are looking exactly the same on phase graph but they are NOT time aligned.

Maybe, but in your argument your are using them interchangeably when they are not in this context.

No your argument has been about 2 things:

. Phase alignment at XO to provide a flat response.
You can have drivers phase aligned and yet not be time aligned. This is precisely how LR4 XOs work.

. A lack of time alignment between drivers being audible.
Well big enough and yes of course it will be, but here we are talking maybe only 1 tenth of a waveform cycle. I suspect you are making guesses about that audibility rather than it being based on any evidence.

 

[QMuse]

Why have you felt the need to exaggerate the scenereo to a ridulous level if you beleive your original point is valid?

To better illustrate the point how things are actually working.

Just because you might hear a difference a 1 second doesn't mean you will hear a difference at 0.005 seconds.

Audible issues usually start at the 3-5ms of misalignement in the LF range.

 

[QMuse]

Maybe, but in your argument your are using them interchangeably when they are not.

Uf..

 

[March Audio]

Audible issues usually start at the 3-5ms of misalignement in the LF range.

So a typical sub won't cause any problems then.

Especially when you consider your mains are also going out of whack down there.

Plus I think you will find its a longer time than that.

Thank you.

 

[QMuse]

So a typical sub won't cause any problems then.

Especially when you consider your mains, are also going out of whack down there.

Thank you.

You don't know the situation in any particular case before you measure the phase and do the alignement. Even passive subs don't align to passive mains just like that and should be phase aligned.

The issue with that is that average audiphille needs some education with that as "integrating subs" is actually a process of making a custom XO between subs and mains, and that is not so easy if you want to do it well.

 

[March Audio]

You don't know the situation in any particular case before you measure the phase and do the alignement. Even passive subs don't align to passive mains just like that and should be phase aligned.

The issue with that is that average audiphille needs some education with that as "integrating subs" is actually a process of making a custom XO between subs and mains, and that is not so easy if you want to do it well.

Oh I agree, I spend a lot of time talking to customers trying to convince them that a sub connected at high level to their mains without proper XO and measurements is a bad idea.

It's difficult to do it well. Personally, for my own use, I wouldn't do this these days without something like Acourate software.