42 minutes ago, Satanica said:

... the best place for subs is rarely in the same proximity as mains.

 

Yes, that's true.    However, my subs can only be located in the place they were planned to be, when the room was designed.  (Front corners - this makes them about 1.5m further away from my ears than the (centre of the) bass panels.)

 

42 minutes ago, Satanica said:

If you crossover 80Hz or lower consider configuring them as mono with the DSP.

 

Can you explain why this would be an advantage over the L sub getting the L signal ... and the R sub getting the R signal?

 

Thanks,

Andy

 

21 minutes ago, andyr said:

Yes, that's true.    However, my subs can only be located in the place they were planned to be, when the room was designed.  (Front corners - this makes them about 1.5m further away from my ears than the (centre of the) bass panels.)

 

Can you explain why this would be an advantage over the L sub getting the L signal ... and the R sub getting the R signal?

The advantage is you can position them wherever is best in the room.

The best position(s) are most likely not in corners.

Symmetrical positioning might look the best but most likely won't be the best.

The Harman white paper is definitely worth a read: https://www.harman.com/sites/default/files/multsubs_0.pdf

If you want to go straight to the conclusion go to slides 74, 75 and 76.

 

Even if you have nowhere else to put them but the front corners of your room I still think you should consider summing the L and R signal into mono.

Then they'll be working together as a unit and should reduce the effect of room modes.

Edited August 29, 20196 yr by Satanica

25 minutes ago, Satanica said:

The best position(s) are most likely not in corners.

 

Understood - but the listening room is not a 'mancave'.    (So I'm not free to do what might be best.)

 

25 minutes ago, Satanica said:

If you want to go straight to the conclusion go to slides 74, 75 and 76.

 

Did that.  Can't see any mention of summing to mono???  Only multiple subs.

 

25 minutes ago, Satanica said:

Then they'll be working together as a unit and should reduce the effect of room modes.

 

I find that difficult to understand???

 

In what way would 2 subs, each working in mono, reduce the effect of room modes ... compared to the same 2 subs in the same positions, working in stereo?

 

25 minutes ago, Satanica said:

Even if you have nowhere else to put them but the front corners of your room I still think you should consider summing the L and R signal into mono.

 

I'm afraid I'm the kinda guy who needs to have some solid reasoning why this is a good idea, before I consider it. 

 

If  I try it ... I presume I use the 'Routing' feature in the miniDSP plug-in to pass L and R inputs to both sub channels?

 

Andy

 

I think summing to 2 subs effectively gives you a multi-sub system. More bass sources (under 80Hz) does even out in room bass response.  

It should be easy to set up in your minidsp - maybe worth a try??

31 minutes ago, AudioGeek said:

I think summing to 2 subs effectively gives you a multi-sub system. More bass sources (under 80Hz) does even out in room bass response.  

It should be easy to set up in your minidsp - maybe worth a try??

 

Sorry, AG - I'm not getting it??? 

 

I already have a multi-sub (2 subs) system.  So I already have 2 bass sources ... which should even out in-room bass response?  So what is delivering these 2 subs in mono going to do?

 

Andy

 

 

 

Yeah, i am not good at explaining things.

 

I imagine all the bass (left and right channel summed) from 2 sources is truly multi-sub  -compared to some bass from each sub (left channel only from 1 and right channel only from 1). I say this as I recently went through this process. With some measurement and tuning in your minidsp it could make a worthwhile improvement.

3 minutes ago, AudioGeek said:

Yeah, i am not good at explaining things.

 

I imagine all the bass (left and right channel summed) from 2 sources is truly multi-sub  -compared to some bass from each sub (left channel only from 1 and right channel only from 1). I say this as I recently went through this process. With some measurement and tuning in your minidsp it could make a worthwhile improvement.

 

Aah, OK - thanks for the explanation, AG.

 

I value people's actual experience (rather than theory).    But when you say you "recently went through this process" ... if you were using a miniDSP unit, can you tell me what you had to do - in the plug-in - to sum L&R into each sub channel?

 

But I can't see why I need to do any (REW) measurement/resetting of miniDSP gain levels?  (Why would summing L&R into a sub increase its volume?)

 

Andy

 

Sorry, I was using a Najda unit - not minidsp.

 

Bass/room coupling may mean the subs present diffetent responses at the listening position when summed  and timing/phase may need separate adjustment. Measurement may also let you dial in the bass curve you prefer - there will still be peaks/dips.

Most low bass recorded in music is relatively mono anyway, and in vinyl it is often intentionally mixed to be mono even further. I seriously doubt there would be any advantage to forcing the subs to be mono.

17 hours ago, andyr said:

Did that.  Can't see any mention of summing to mono???  Only multiple subs.

The article is of the assumption of mono sub-woofers so they can be placed anywhere in the room.

Mid wall front and back for two sub-woofers was found to be best.

13 hours ago, Ittaku said:

Most low bass recorded in music is relatively mono anyway, and in vinyl it is often intentionally mixed to be mono even further. I seriously doubt there would be any advantage to forcing the subs to be mono.

If that's the case then you couldn't seriously doubt it would do any harm either right?

13 hours ago, andyr said:

But when you say you "recently went through this process" ... if you were using a miniDSP unit, can you tell me what you had to do - in the plug-in - to sum L&R into each sub channel?

Section 3 of:

 

https://www.minidsp.com/applications/digital-crossovers/subwoofer-integration-with-minidsp

Edited August 30, 20196 yr by Satanica

52 minutes ago, Satanica said:

If that's the case then you couldn't seriously doubt it would do any harm either right?

So why add the complexity of another filter into the DSP if it does no good? It's actually simpler as it currently is. The research was done with mono subs in order to find the optimal placement. Andy doesn't have that luxury as the sub locations are fixed at far left and right front.

Edited August 30, 20196 yr by Ittaku

42 minutes ago, Ittaku said:

So why add the complexity of another filter into the DSP if it does no good? It's actually simpler as it currently is. The research was done with mono subs in order to find the optimal placement. Andy doesn't have that luxury as the sub locations are fixed at far left and right front.

It's not another filter it's a summation. I think it will do good as it should result in a better frequency response below the crossover point. Simpler does not mean better but I understand that typical audiophile law says otherwise.

Just now, Satanica said:

It's not another filter it's a summation. I think it will do good as it should result in a better frequency response below the crossover point. Simpler does not mean better but I understand that typical audiophile law says otherwise.

You're still not making an argument for how exactly it's supposed to result in a better frequency response. Just because all research was done with mono subs does not mean stereo subs will definitely perform better in mono...

7 minutes ago, Ittaku said:

You're still not making an argument for how exactly it's supposed to result in a better frequency response. Just because all research was done with mono subs does not mean stereo subs will definitely perform better in mono...

It gives more freedom of movement.

You don't have to be anal about setting them up with perfect symmetry.

Granted in this example there is little wiggle room but even moving a sub an inch will change it's frequency response at the listening position.

So, I would still do it just like the miniDSP sub-woofer integration guide specifies.

Just now, Satanica said:

It gives more freedom of movement.

We already said Andy has absolutely ZERO freedom with the positioning of his subs. The room was built around the subs' position!

2 minutes ago, Ittaku said:

We already said Andy has absolutely ZERO freedom with the positioning of his subs. The room was built around the subs' position!

I read that but I find it hard to believe they can't be moved an inch in at least one direction.

 

You're sounding angry, take a chill pill. ?

1 minute ago, Satanica said:

I read that but I find it hard to believe they can't be moved an inch in at least one direction.

 

You're sounding angry, take a chill pill. ?

sorry for the uppercase, it was emphasis only. to not sound angry i'm only using lowercase in this post even though it kills me to screw up punctuation.

 

But I can't imagine 2.5cm making any difference whatsoever to be honest, with waveforms >=2m long.

Edited August 30, 20196 yr by Ittaku

20 hours ago, andyr said:

Can you explain why this would be an advantage over the L sub getting the L signal ... and the R sub getting the R signal?

If, there is any stereo bass content on the recording ... then it is better to mix that electronically .... rather than let the soundwaves in the room do the mixing.

 

It might seem intuitive to say "but but what about, I can hear the stereo bass".   You can't.    There are a few ways to do testing where it can make it seem like we can hear stereo bass..... but we can't.     What you're hearing in the tests are just different examples of how the waves mix together.   They're all flawed, just flawed differently,  and so sound different from each other..... but this doesn't mean we actually hear bass in stereo.

 

 

That being said.   I'd limit this to ~80 with a steep rolloff (24dB/octave)

15 hours ago, andyr said:

I value people's actual experience (rather than theory)

I believe this is mostly a mistake.

 

"Experience" is "subjective".... and relies on assumptions, including that the experience was reported "correctly" .... but people are much more fallibale than we like to think.

 

Also the "experience" typically doesn't explain WHY  the thing is happening, and under what circumstances we should expect it to be repeated.

 

"Theory" on the other hand..... is based on objective observation and testing (disproving) ..... and has a reasoning  / justification / explanation attached to it.   So we can make reasonings about how likely the theory is to apply to a certain situation... and what to expect and why.

 

 

A paradox here is that it is easy to misapply theory..... and this is often what trips people up.    They observe (or hear about) someone misapplying theory ..... the result is bad..... and the conclusion is that "theory is wrong or unreliable."

 

... but we are just back at the problem I mentioned earlier 

Quote

people are much more fallibale than we like to think

 

We like to blame theory, rather than blame the person.    We like to trust and forgive people (it is human nature) .... but we don't like place trust theory (when we don't understand it or have any reason to believe it is reliable).

1 hour ago, Ittaku said:

So why add the complexity of another filter into the DSP if it does no good?

It is likely to do good.

 

Stereo bass will be a mess no matter what happens, and is thus a prickly topic  ..... and unless you have a very very specific objective (as a producer) it is unwise to record it, or leave it in a recording.

 

Even if there is a specific objective you're unlikely to be rewarded, as you can't control how it is reproduced.    There's really only going to be 3 broad options.

 

• It is sent to mono in the electronics  (this is what you should really expect, as it is considered best practice)
• It is played on headphones   (in which you might try it, and give people a head tickle)
• It is produced by stereo subwoofers in a room .... and will be heard at best by people in mono....  but the resulting frequency response (and so the sound) will be unpredictable depending on the room dimensions, and location of source and listener.

There is a disconnect here that people are missing which both Andy and I are questioning.

 

There is research that shows we can't hear the directionality of frequencies below 80Hz, therefore mono subs are fine. Fine, acknowledged.

There is research that shows that placing two mono subs works best at middle front and rear or middle left and right side walls to more smoothly fill out bass frequencies. Fine, acknowledged.

 

The research showed that mono subs are fine, not that they're better. Where is the research that shows that shows that mono subs are better than stereo subs (and add to that - when positioned at the front wall?)

On 28/08/2019 at 9:15 PM, andyr said:

So I will set up 4 configs in my miniDSP unit - identical except that the sub/bass panel XO is progressively lowered from:

• 100Hz
• to 80Hz
• to 60Hz
• to 50Hz

... and we will see which one sounds best.    (Same 24dB HP & LP slopes in each.)

Would it be worthwhile trying higher crossover points with gentle slopes too? It looks like an easy free experiment which might give interesting results with mid-bass rich music,  like acoustic bass in jazz.

 

Is there a current photo of your room and system to get an appreciation of what your doing?

 

On 30/08/2019 at 2:56 PM, Nada said:

Would it be worthwhile trying higher crossover points with gentle slopes too? It looks like an easy free experiment which might give interesting results with mid-bass rich music,  like acoustic bass in jazz.

 

Yes, it's a simple thing to do, N ... but I can't see any logic for lowering the XO slopes/raising the XO point?

 

As always - the change is quick ... but then you need to spend tome testing whether the new setup actually does sound better. 

 

On 30/08/2019 at 2:56 PM, Nada said:

 

Is there a current photo of your room and system to get an appreciation of what your doing?

 

 

Does this help?

 

 

 

The edge of the listening couch is shown in the bottom left corner of the pic.

The L sub is in the front corner, hidden by the L Maggie (under that laminated benchtop).

 

Andy