MiniDSP subwoofer calibration/integration microphone position dilemma

Mr Wolf

Well-known Member
Here's the thing. I've just bought a MiniDSP 2X4HD and now have a bit of a dilemma about where to position the UMIK-1 for subwoofer calibration/integration purposes.

The dilemma stems from the fact that neither of the two seats that are used >90% of the time (seats #2 and #3 in picture below) are in the centre line of the room. The seating comprises a 3-seater sofa where only the left and right seats recline so they're the ones we use when watching. The upright centre seat #1 is only used very rarely.

1630063406502.png


Seats #2 and #3 are 59cm off the centre line of the room and about 15cm further back and lower than position #1 due being reclined.

The room is roughly 5.7Mx5.4M and largely symmetrical but not perfectly so acoustically mainly due to the window and door positions (see below). The two subs are in the rear corners of the room and are symmetrical to the listening seats.

1630064088071.png


My dilemma is which microphone positions to use for level matching, time alignment and EQing the subs.

These are the options I'm considering.

Option 1: Do everything at my seat (position #2). The basis being that I'm the only one who's critical about this stuff and the Mrs probably won't notice or care. That said, I wouldn't want to trash the sound at seat #3 for only a small gain at seat #2.

Option 2: Level match and time align the subs to position #4 which is a mid-point between seats #2 and #3 but EQ the subs at my seat, position #2. The basis being that due to room symmetry positions #2 and #3 from an EQ perspective should be very similar but my seat will have the edge.

Option 3: Do everything at the mid-point position #4. This keeps things simple but I don't like the idea of EQing to a position where nobody sits, especially as it's the centre line of the room where it should get more nulls.

Instinctively I'm drawn towards Option #2 but wondered if anyone had any thoughts or different ideas? What would you do if this were your room?
 

mb3195

Distinguished Member
Would your Mrs realistically notice? If not, be completely selfish and calibrate it entirely for your benefit!!!

The other options are using MSO for multiple seat calibrations, or thirdly in the middle of the 2 seats.

Personally I would do option 1! 😂
 

Mr Wolf

Well-known Member
Would your Mrs realistically notice? If not, be completely selfish and calibrate it entirely for your benefit!!!

The other options are using MSO for multiple seat calibrations, or thirdly in the middle of the 2 seats.

Personally I would do option 1! 😂
Good thinking, I’m sure she wouldn’t notice a thing and my slight of hand would go undetected…mwhahahahaha!

I’m really trying to get my head around what in practice I’d actually be giving up though with Option 2 which should in theory create two very even seats. OK, the subs wouldn’t be level matched at my seat but they would be making a more even contribution so that’s not a bad thing. They should be about 2ms out on being time aligned at both used seats so they wouldn’t be as efficient due to a lower level of summation. But surely that output differences will be made up at the EQ stage done at my seat so FR should hopefully still be good but the negative would be that it would have a lower amount of headroom. Is that right?

Think I may just run both options 1 and 2 and save them in the MiniDSP config memories (damit, wish I’d bought the remote now) and compare the seat to seat results in REW for each option.
 

markymiles

Distinguished Member
Yep totally agree. They don't get a say, I'm in the same boat down one the end of the sofa and it's all about me haha. Option 1 all the way. No harm in trying the others and seeing how much variance you have seat to seat
 

Conrad

Moderator
I do option 1 and then check my wife's seat at the end. If it's awful then I adjust.

I've found that being only about 1m away there's very little difference (and we're either side of the line of symmetry in the room). We don't have a seat between us though.
 

mb3195

Distinguished Member
Good thinking, I’m sure she wouldn’t notice a thing and my slight of hand would go undetected…mwhahahahaha!

I’m really trying to get my head around what in practice I’d actually be giving up though with Option 2 which should in theory create two very even seats. OK, the subs wouldn’t be level matched at my seat but they would be making a more even contribution so that’s not a bad thing. They should be about 2ms out on being time aligned at both used seats so they wouldn’t be as efficient due to a lower level of summation. But surely that output differences will be made up at the EQ stage done at my seat so FR should hopefully still be good but the negative would be that it would have a lower amount of headroom. Is that right?

Think I may just run both options 1 and 2 and save them in the MiniDSP config memories (damit, wish I’d bought the remote now) and compare the seat to seat results in REW for each option.
I’d doubt you’d hear that much difference between the seats, just go with option 1 and then forget about it. No one but you will ever know.
 

IWC Dopplel

Distinguished Member
Maybe its just me, but I'd try and get the performance even across the whole seat, I find if a room is set up to be too focussed on a small area, that measures well but often if the room sound good over a wide ares it somehow seems more integrated and engaging
 

Mr Wolf

Well-known Member
Quick update.

The difference in FR at my seat between options #1 and #2 was so tiny when I measured it that I decided in the end to go with option #2 to ensure a better result at my wife's seat.

This is the FR graph (no smoothing) across the three seats with a 10dB House Curve.

1630594153182.jpeg


The black line is my seat where I did the EQ, the red is my wife's seat and lower green one is the centre seat. The upper blueish line is the un-EQ'd FR at my seat so thank heaven for MiniDSPs!

Looking at the red line (wife's seat), apart from the dip around 30Hz the room symmetry held up really well to create a very similar FR to my own seat so I'm fairly pleased with this result. Watched a movie last night with this config and the bass sounded very smooth.
 
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Dobbyisfree

Well-known Member
I completely agree that "the other person" wouldn't notice it with the subs.

However, this is interesting, as I have the same dilemma with our sofa. The centre position isn't sat in yet is the ideal MLP. I'm only using XT32 with sub eq ht.

What doesn't work is EQing for your seat (whether that's left or right, in my case the RHS) for the other speakers. In my case, it was clearly audible to my wife that the surrounds were too loud on that side.

Hence, I re-ran the EQ for the centre position and, to be honest, it's fine!
 

Mr Wolf

Well-known Member
What doesn't work is EQing for your seat (whether that's left or right, in my case the RHS) for the other speakers. In my case, it was clearly audible to my wife that the surrounds were too loud on that side.
I agree. My speaker channel levels are all calibrated for the centre seat. As the viewing seats are only 59cm either side of the calibration point, the SPL from all speaker channels is within a 1dB deviation at both seats.
 

Dobbyisfree

Well-known Member
Yeah, I know I was a bit off topic but thought it worth mentioning to stop anyone wasting EQ time (like I did, XT32 set LH surround 2.5dB higher and my wife said she couldn't hear the front speakers!).

It's also worth considering, with subs (depending on their position etc), if they are symmetrical and you EQ them in the centre, you get maximum output from both. Whereas off to one side one sub will hit peak before the other.

This may not matter if you have 21" coffins with 1000w amps in - but for me and my old Storms, I need every dB of bass I can get 🤣
 

Mr Wolf

Well-known Member
Even in non-symmetrical rooms some people still choose to gain match rather than level match their subs so that they each have the same headroom level.

Fortunately in my case level matching = gain matching and no time alignment was required either. In fact I could now hook the subs to just one output of the MiniDSP via a y-splitter as I'm only using it to EQ the subs. This may come in handy if I ever run four subs as I only wired the room for one subwoofer cable at the back of the room. RoomSIM suggests that one in each corner would be my best subwoofer config by far.
 

AndreNewman

Active Member
The trouble with eq-ing for just your seat is if by chance the Mrs' seat gets a big bass peak, she'll be telling/asking you to turn it down all the time!

Voice of experience...
 

Mr Wolf

Well-known Member
Fortunately she likes the bass peaks as much as me and the FR in her seat (red line) is never more than about 1dB more than mine.

TBH I'm really pleased how she's taken a liking to the new subs. When I ordered them she thought I was being really extravagant spending that much but now she gets it and sees the value in them.
 

Jester1066

Well-known Member
TBH I'm really pleased how she's taken a liking to the new subs. When I ordered them she thought I was being really extravagant spending that much but now she gets it and sees the value in them.
Well. You sir, have achieved the Holy Grail there and will be the envy of many a forum member me thinks! 🤣
 

Dobbyisfree

Well-known Member
Don't let her out on her own... particularly if it's one of those special pubs for AV geeks 🤣
 

Mr Wolf

Well-known Member
Don't let her out on her own... particularly if it's one of those special pubs for AV geeks 🤣
Certainly not..that’s where I met her!

My next challenge is to get the sign-off on a 13.1 AVR past her…and then a 4K projector. Something may have to “break” for me to pull those two off in the 12 months!
 

Jester1066

Well-known Member
Certainly not..that’s where I met her!

My next challenge is to get the sign-off on a 13.1 AVR past her…and then a 4K projector. Something may have to “break” for me to pull those two off in the 12 months!
🤣🤣🤣

We seem to be on a similar audio journey mate. I face a similar challenge regarding a 4K projector. Alas, my (non dedicated) room will not accomodate anything above a 5.2.4 configuration. The fact that I've achieved this in what is essentially the living room, I consider a major "win".... So I think I'll hold off on project projector for a while! 🤣
 

Fred777

Active Member
The black line is my seat where I did the EQ, the red is my wife's seat and lower green one is the centre seat. The upper blueish line is the un-EQ'd FR at my seat so thank heaven for MiniDSPs!
Wolf, amazing to see how the minDSP has significantly flattened your FR - awesome! I am also jealous of your room - my living room is very limited with speaker placements.

I actually share one thing in common with your FR, and that is the big dip between 95-100Hz. Is your FR on that graph with subs only, or is that playing with a LCR speaker also?

As others have mentioned, it might worth giving MSO a try for multiple positions since you have the miniDSP now. It looks reasonably straight forward and works out all the possible combinations for you. In saying that, you have an excellent response across all 3 seats so it's nit-picking. I am in a similar boat where I have to decide whether I EQ for my seat, or across 3 seats. I have a problem where me/wife don't always sit in the same spot, so depending on my choice I'll have to fight for the centre spot hehe
 

Mr Wolf

Well-known Member
I am also jealous of your room - my living room is very limited with speaker placements.
Don’t worry, so does my living room! This is a dedicated HT room that I created by remodelling the second floor of the house. The room is definitely the greatest strength of the system though. Until it was built this equipment (minus the new subs and the projector) was in my living room and I couldn’t believe the improvement in sound in the new room. The width of the room helps present a very large soundstage and nobody sits too close to any surround speaker.

I actually share one thing in common with your FR, and that is the big dip between 95-100Hz. Is your FR on that graph with subs only, or is that playing with a LCR speaker also?
This is just the subs so probably due to SBIR but as it’s past the 80Hz crossover the mains, if positioned well, to a greater extent fill this in. Gene at Audioholics has said not too worry too much about very narrow Q dips. What interesting is they don’t always appear when you re-run the sweep.

Wolf, amazing to see how the minDSP has significantly flattened your FR - awesome!
I should add that to get the black line that flat I had to use 5 of the manual filters to polish off the auto-EQ’d line. I was expecting the left and right seats to be very even though as RoomSIM showed them to be identical if the layout was symmetrical which it almost is.
 

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