On 30/08/2019 at 1:34 PM, Ittaku said:

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?)

I can't point to any research but Dave has pointed out that stereo bass will be summing in your room versus mono bass that will be summing in digital electronics.

I think it's pretty obvious which one will most likely be fraught with problems.

16 minutes ago, Satanica said:

 

I think it's pretty obvious which one will most likely be fraught with problems.

 

 

Well, it's certainly not obvious to me , S, which one (stereo bass in your room versus 2x mono bass that have been summed in the miniDSP) will be more problematical! 

 

All that I can see is that the sub frequ range will be louder if I add R & L for each sub - compared to just the R signal going to the R sub and the L signal going to the L sub (as each sub has R+L feeding it = 2x R plus 2x L, in total).

 

Andy

 

Have come in a bit late on this and havent read the entire thread and hope I am have not got this all wrong but isnt it all about unwanted interactions? If you run the 2 subs in stereo and dsp them both to be flat by themselves and say you listen to a Beatles track where Paul McCartney is on the left only then it should be totally predictable what will happen in the bass. It should be good and flat. But What if you listen to another track where the bass is a 1/3 of the way across the stage. Well it might be good or it might not. If you measured each individually then you dont know how they sum acoustically and you will also have interaction with the panels at some frequencies. If you sum them and measure, no matter where the bass is in the sounds stage it will always be as predicted. There is offcourse still the wrinkle of the panels as they are in stereo but the majority of bass will be as flat as you make it wilth dsp .  Or another thought is  use the MSO method to setup the subs for a flatter response over a larger listening area

13 hours ago, frednork said:

Have come in a bit late on this and havent read the entire thread and hope I am have not got this all wrong but isnt it all about unwanted interactions? If you run the 2 subs in stereo and dsp them both to be flat by themselves and say you listen to a Beatles track where Paul McCartney is on the left only then it should be totally predictable what will happen in the bass. It should be good and flat. But What if you listen to another track where the bass is a 1/3 of the way across the stage. Well it might be good or it might not. If you measured each individually then you dont know how they sum acoustically and you will also have interaction with the panels at some frequencies. If you sum them and measure, no matter where the bass is in the sounds stage it will always be as predicted. There is offcourse still the wrinkle of the panels as they are in stereo but the majority of bass will be as flat as you make it wilth dsp .  Or another thought is  use the MSO method to setup the subs for a flatter response over a larger listening area

 

Thanks, fn.    Yes, you have it right.

 

Don't know the 'MSO method'?

 

Andy

 

 

 

My "MSO" technique is to go to a Melbourne Symphony Orchestra concert and listen to the bass there and tweak mine at home to sound close to it.

1 hour ago, frednork said:

 

 

 

Thanks, fn. 

 

That looks very interesting - as it seems to have some actual logic behind it (rather than an heuristic recommendation!).    Although I notice it is aimed at AV setups (with its reference to AVRs & multi-seat setups).

 

I will investigate it further!

 

Andy

 

Edited September 2, 20196 yr by andyr

Welcome to the topic of MSO @andyr !  I have not been following this topic, so pls excuse me if I misread something posted earlier.

 

MSO uses mono bass, so the L & R source is summed, less 6 dB. MSO will recommend gain, delay, crossover and PEQs for each sub so that the bass from the subs "fills in" the bass of the mains. It breaks conventional thinking on what the phase and cross over should be. I do not know the theory behind it nor can I debate the merits of adjusting certain parameters (can invite author to thread if required). 

 

My listening experience suggests that MSO is very good in evening bass in the room and across seating positions. 

Edited September 3, 20196 yr by Snoopy8
Typo

 
Thanks, S - but I have stereo subs.  So 'locating the (one) sub' - from having a too-high XO - is not an issue.
 
Andy
 

Depending on how close you are to the subs, you might be able to locate the subs with signals above 80Hz.

In my room sitting not in the center,But tintje peft or right, I was able to hear the signal jump from speaker to sub at a 100Hz. With 80Hz, that is no longer a problem.

19 minutes ago, Primare Knob said:

Depending on how close you are to the subs, you might be able to locate the subs with signals above 80Hz.

In my room sitting not in the center,But tintje peft or right, I was able to hear the signal jump from speaker to sub at a 100Hz. With 80Hz, that is no longer a problem.

 

Sitting anywhere on my couch, Maarten (so 3 listening positions) I cannot tell that the subs are on.  All I hear is that the Maggies suddenly seem to have bass weight! 

 

Andy

 

18 hours ago, andyr said:

Well, it's certainly not obvious to me , S, which one (stereo bass in your room versus 2x mono bass that have been summed in the miniDSP) will be more problematical! 

You can lead a horse to water but ... ?

 

Frednork has illustrated it should be much easier to get flatter bass in the mono range that the subs would be working in.

 

MSO is just a bass improvement/tuning procedure based around two or more mono subs and multiple listening areas.

You don't need MSO to use mono subs.

There is quite a learning curve to use it.

I have doubts that it is for you and I only mean that in that it's quite complex and time consuming.

I'm sure you could use it if you really wanted to.

 

This is where you should go next regarding the miniDSP and mono subs if not already done so:

https://www.minidsp.com/applications/home-theater-tuning/tuning-multiple-subs

There are three bass integration methods A, B and C with MSO being method C and it is seemingly the ultimate that can be achieved with a miniDSP and REW.

Edited September 3, 20196 yr by Satanica

I still see leaps of faith between different facts, but I give up debating it.

6 minutes ago, Ittaku said:

I still see leaps of faith between different facts, but I give up debating it.

I haven't heard one argument from you that things could be worse.

So why not apply it when it takes minutes?

 

Your leap of faith is that things can't be improved or worsened or just plain changed even; they will stay exactly the same.

I don't think many if any are believing it.

 

And it is industry best practice after-all and has been for a very long time.

Aah, bugger!    Can't do any more testing - or even listening - for a while as I've just confirmed my L bass panel buzzes on certain music.  (It's not my CDP, @genkifd - I borrowed someone else's CDP which also buzzed!  )

 

What a bummer! 

 

So I will have to send them up to Bill, in Gosford, for re-laying the wires on the mylar sheet (R panel as well).  Just waiting to hear when he can do this. 

 

(My mids were re-built by Bill about 9 years ago and the glue used now is better than the glue Magnepan used in the 80s.  So they will last forever!    However, my bass panels are original - so it was only a matter of time.  )

 

Andy

 

Bugger!

No one local to you can do this?

Andy,

 

bugger, at least you found the issue. hope all goes well

23 minutes ago, AudioGeek said:

Bugger!

No one local to you can do this?

 

Not that I know, AG. 

 

I re-laid a mid on my previous Maggies - and didn't make a very good job of it.    So I'm not going to do these myself! 

 

Andy

 

That's really sad Andy. Do you think current model Maggies would also be plagued by reliability issues like this that mean they all eventually need to be refurbished somehow, or have they put that issue to bed?

1 hour ago, Ittaku said:

That's really sad Andy. Do you think current model Maggies would also be plagued by reliability issues like this that mean they all eventually need to be refurbished somehow, or have they put that issue to bed?

 

Current model Maggies are fine, Con.  Magnepan changed the glue they use in the early 2000s (IIRC); this later glue doesn't break down like the previous glue did.  My bass panels were mfrd in '87.

 

Andy

 

Jeez, I posted on Sep 7th that I would have to send my bass panels away for a re-wire ... now it's Oct 14th - and I heard a coupla days ago that the work is done    and they should be sent back to me, sometime this week.    Yay!

 

Andy

 

Aah, bugger! 

 

Heard yesterday that Bill McLean's tech wasn't happy with one of the panels he'd re-wired - presumably, the first one he did! - so decided to do it again!

 

Annoying delay - but full marks for their quality control ethos. 

 

But I may have some further delay, before I can get to listen to them.    I requested Bill use the 3mm aluminium foil that Magnepan use on current models, for the re-wire - instead of the original Al round-wire.  I expect this will improve bass panel SQ (otherwise, why would Magnepan be using it!) but it'll probably lower the panel resistance.  If it gets really low ... I will have to lower the DC rail voltage on my bass panel AKSA monoblocs, for them to be able to cope - which means buying 2 new power transformers (with lower secondary voltages).

 

Just waiting to hear what the tech measured the panels' resistances as.

 

Andy

 

Well, today Bill sent me pics of my re-wired panels!  Will be sent back in the next couple of (work) days! 

 

 

 

 

The foil looks really cool!! 

 

He said the measured panel resistance is now >5 ohms - which is actually more than it was with the original round-wire.  Which is unexpected - but welcome! 

 

Can't wait to hear the difference in sound. 

 

Andy

 

Edited October 31, 20196 yr by andyr

That’s fantastic, andy. It’s been a blaady long wait. I’m still waiting for my tweeters. 

Were the old panels 4ohm?

Edited October 31, 20196 yr by buddyev

2 hours ago, buddyev said:

That’s fantastic, andy. It’s been a blaady long wait. I’m still waiting for my tweeters. 

Were the old panels 4ohm?

 

Yes, Russ - old panels were 4 ohms. 

 

Andy

 

Well, unpacking the panels and having a closer look has revealed an issue that I am extremely PO about! 

 

A closeup of the pic above - focussing on the connectors at the bottom of the panels is here:

 

 

 

 

As you can see, the tech made a beautiful job of finishing off the ends of the foil with some 4.8mm spade lugs.  Trouble is ... as you can see, wires are soldered to the solder tabs which the previous round-wire was soldered to - and these wires connect to the banana sockets at the back, which take the spkr cables.

 

So I cannot just connect up my re-wired panels and start listening to music ... I need to f'ing well make a connection between my wires ... and the damn tech's foil spade connectors! 

 

There's an easy - and a complex way of doing this!    The easy way is to use some right-angle 4.8mm spade connectors - which will enable me to simply:

• unsolder my wires from the solder tabs
• and bend them sideways to fit onto the right-angle spade connectors (called - for obvious reasons - 'flag' connectors).

After several hours of searching, I was able to locate some of these from Element14 (most flag connectors - from various mfrs - fit 6.3mm spades!  ).  So hopefully they will arrive tomorrow ... and I can see whether they will work as planned.

 

Andy

 

Edited November 14, 20196 yr by andyr