Question about dual sub, rew and allignment

[Pieter1267]

So i now have 2 dayton 15" ultimax subwoofers. Number one is ultimax mki and sub 2 is ultimax mkii

In the rew they have slightly different output. In the many great utube videos on multi sub eq ing they all say forget individual outpyt, look at the aligned output and make an eq with rew on that, for both subs.

Heres where i dont follow. If you have different subs dont you need different peq files for each? Or how do you approach?

In practise, 2 spec peq files doesnt sound or measure as good as having both on the same peq file.

 

[sigbergaudio]

Both approaches can work. I don't think one method would universally and always be better than the other, it depends.

You can EQ the combined output of both subs. In this case you would apply the same EQ to both subs.

Or you can measure them individually and EQ them individually. In this case you need at some point to measure them combined to see that you get the combined result you are after.

 

[Pieter1267]

Both approaches can work. I don't think one method would universally and always be better than the other, it depends.

You can EQ the combined output of both subs. In this case you would apply the same EQ to both subs.

Or you can measure them individually and EQ them individually. In this case you need at some point to measure them combined to see that you get the combined result you are after.

Thank you! Another question: do you start the aligning with measuring the subs individually or from Listening Position?

 

[sigbergaudio]

Thank you! Another question: do you start the aligning with measuring the subs individually or from Listening Position?

In both situations you would measure from the listening position, as this is where you want even bass.

 

[DaveBoswell]

I have looked at over 20 multi sub setups for HT using a great free tool called Multi Sub Optimizer (aka MSO) and for most normal sized listening rooms, the best results where subs are time/phase aligned for minimal cancellation and maximum output, are found where all subs have the same PEQ below about 50Hz or so, and then each individual sub has a small amount (+/- 3dB or so) of different PEQ applied between 50Hz and 200Hz. This small variation of PEQ above 50Hz helps to reduce the seat to seat variation and smooths the peaks and valleys in the upper bass region in a larger area.

Best results are achieved by measuring each sub and multiple positions - say 1 Main Listening Position and 2 other positions Left and Right say 45-60cm away - even if you are normally the only person listening. It works even better with more than 2 subs, but 2 subs is vastly preferable to 1 single sub.

I've got a video in my signature that goes through the basic setup parameters and some more advanced techniques using MSO if you are interested.

 

[Pieter1267]

I have looked at over 20 multi sub setups for HT using a great free tool called Multi Sub Optimizer (aka MSO) and for most normal sized listening rooms, the best results where subs are time/phase aligned for minimal cancellation and maximum output, are found where all subs have the same PEQ below about 50Hz or so, and then each individual sub has a small amount (+/- 3dB or so) of different PEQ applied between 50Hz and 200Hz. This small variation of PEQ above 50Hz helps to reduce the seat to seat variation and smooths the peaks and valleys in the upper bass region in a larger area.

Best results are achieved by measuring each sub and multiple positions - say 1 Main Listening Position and 2 other positions Left and Right say 45-60cm away - even if you are normally the only person listening. It works even better with more than 2 subs, but 2 subs is vastly preferable to 1 single sub.

I've got a video in my signature that goes through the basic setup parameters and some more advanced techniques using MSO if you are interested.

Thanks! I put so much time in researching rew that for today its enough. Mso research is in the planning though.

I tried same peq for both but the individual files per sub ended up the best option. I made sure autorew didnt push or pull anything above 4db. It looks amazingly flat and im content.

What does mso offer above rew?

 

[Pieter1267]

Something not right. The green and orange line are individual sub. The blue line is together. No alterations. Any idea why its measuring lower spl? Its audible too.

 

[Flaesh]

Something not right.

That's weird. Did you check the polarity?

 

[Pieter1267]

That's weird. Did you check the polarity?

I didnt change or move anything. The blue line was measured a minute after the individual. I did notice a few days ago how the umik 1 gives a big difference in spl after moving just a few inches. Maybe the umik1 is faulty.

 

[Pieter1267]

New measurement, umik1 callibrated. Again. Is this normal? Together they give less spl untill 45hz than individually EDIT: maybe this actually is THE reason why 2 subs are better than one single? Maybe we are looking at the measured proof 2 subs make a smoother but also lower output at lower frequencies?

 

[sigbergaudio]

It will typically be the other way around (more SPL with both playing).

 

[Pieter1267]

It will typically be the other way around (more SPL with both playing).

..the mind boggles. Maybe MINIDSP is messing. Ill go do some further adjustments. Thanks for confirming this isnt normal.

 

[Flaesh]

This is abnormal and disgusting. Have you checked the polarity?

 

[Pieter1267]

This is abnormal and disgusting. Have you checked the polarity?

Disgusting?

Polarity is fine. There is no change between measurements individually and both.

 

[Keith_W]

What does mso offer above rew?

MSO relies on REW for taking measurements for processing. REW is not DSP software, it is primarily for taking measurements. If you want to make corrections, the tools available in REW are fairly rudimentary. You need third party software to give you more tools - MSO and RePhase.

Why two subs are softer than individual measurements of one sub: they may be out-of-phase. Try this: use Trace Arithmetic A+B and add the two subs together. It should look like the actual measurement of both subs. This is what @Flaesh was trying to say. Polarity is not the only reason subwoofers may behave as if they are out-of-phase, there may be other reasons such as room configuration, asymmetric reflections, etc.

As for your measurements, please read this thread and make sure you are taking measurements correctly.

 

[Flaesh]

Polarity is fine.

What happens if you invert one sub?

 

[sigbergaudio]

How are the subs placed?

 

[Pieter1267]

MSO relies on REW for taking measurements for processing. REW is not DSP software, it is primarily for taking measurements. If you want to make corrections, the tools available in REW are fairly rudimentary. You need third party software to give you more tools - MSO and RePhase.

Why two subs are softer than individual measurements of one sub: they may be out-of-phase. Try this: use Trace Arithmetic A+B and add the two subs together. It should look like the actual measurement of both subs. This is what @Flaesh was trying to say. Polarity is not the only reason subwoofers may behave as if they are out-of-phase, there may be other reasons such as room configuration, asymmetric reflections, etc.

As for your measurements, please read this thread and make sure you are taking measurements correctly.

Thanks Keith. That article written by you made me get a proper mic stand 2 months ago.

Thanks @Flaesh @sigbergaudio
I noticed minidsp still has some dirac adjustments on input.

Ill go and reset everything and now dig into the mso tutorial. Ill also check and recheck the polarity, see what happens when invert but individually they look quite similar. I cant imagine i made a mistake on one of the connection. Illl get back when new adjustments are done.

Its a rather small rectangular room. Subs are in opposite corners. One of them has a huge relax chair standing close.

 

[sigbergaudio]

Thanks Keith. That article written by you made me get a proper mic stand 2 months ago.

Thanks @Flaesh @sigbergaudio
I noticed minidsp still has some dirac adjustments on input.

Ill go and reset everything and now dig into the mso tutorial. Ill also check and recheck the polarity, see what happens when invert but individually they look quite similar. I cant imagine i made a mistake on one of the connection. Illl get back when new adjustments are done.

Its a rather small rectangular room. Subs are in opposite corners. One of them has a huge relax chair standing close.

I wouldn't start with MSO before you get the basics right in REW.

 

[Flaesh]

If the .mdat file is saved, you can try inverting one sub in the file and see A+B, as @Keith_W said.