Help/Advice Wanted - REW, Lyngdorf 3400, M&Ks and REL Sub - Room Mode Null Issues

benzi

Active Member
Hi All,
Finally getting around to finalising new setup and getting a bit stuck with subwoofer....I'm well and truly down a rabbit hole...

@Gasp3621 @Conrad - I'm new to REW - I think I've got outputs correct but different to Room Sim which makes sense as room isn't perfect rectangle. Please can you provide some input as to how I could resolve this issue? Do I need to go dual or more subwoofers to resolve the null issue in my room?
Many thanks, Benzi

Current setup:
Yamaha RXA 3070 & Lyngdorf TDAI 3400
M&K Sound MP300 LCR
1 x Rel T9x (purely for aesthetics) but open to changing as long as it is white....

I've had a number of subs - Rel T5s, Rel Carbon Special, SVS SB 3000, BK Gemini etc.... but have normally allowed Yamaha YPAO to calibrate or more recently the Lyngdorf to run Room Perfect. Whilst I've largely been happy with the sound quality.....something isn't quite right with the subwoofer setup - most likely user error/lack of understanding.

I've bought a UMIK and run REW to understand a bit more about the room and from my initial outputs it look likes I've got a pretty big null (40Hz to 55Hz), whether I position sub in left/right corner or under centre speaker.
Room Modes 20-04-22.jpg

The room is 4.9m by 4.9m x 2.9m high with chimney breast, alcoves and bay window making it a challenging room to get right. MLP is in bay window about 4.25m away from screen/speakers:
IMG_20220319_171943.jpg


Any advice would be gladly received! Thank you
 

maxkolonko123

Well-known Member
Hi All,
Finally getting around to finalising new setup and getting a bit stuck with subwoofer....I'm well and truly down a rabbit hole...

@Gasp3621 @Conrad - I'm new to REW - I think I've got outputs correct but different to Room Sim which makes sense as room isn't perfect rectangle. Please can you provide some input as to how I could resolve this issue? Do I need to go dual or more subwoofers to resolve the null issue in my room?
Many thanks, Benzi

Current setup:
Yamaha RXA 3070 & Lyngdorf TDAI 3400
M&K Sound MP300 LCR
1 x Rel T9x (purely for aesthetics) but open to changing as long as it is white....

I've had a number of subs - Rel T5s, Rel Carbon Special, SVS SB 3000, BK Gemini etc.... but have normally allowed Yamaha YPAO to calibrate or more recently the Lyngdorf to run Room Perfect. Whilst I've largely been happy with the sound quality.....something isn't quite right with the subwoofer setup - most likely user error/lack of understanding.

I've bought a UMIK and run REW to understand a bit more about the room and from my initial outputs it look likes I've got a pretty big null (40Hz to 55Hz), whether I position sub in left/right corner or under centre speaker.View attachment 1686104
The room is 4.9m by 4.9m x 2.9m high with chimney breast, alcoves and bay window making it a challenging room to get right. MLP is in bay window about 4.25m away from screen/speakers:
View attachment 1686107

Any advice would be gladly received! Thank you
Did you tried to move your mic from MLP closer to TV? And see if this null change? You have nice space so can try to run around with mic and see how it looks in different spots 😅
 
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Conrad

Moderator
I would also try measuring the sub in different places in the room, even if they're not practical long term. A long subwoofer cable from amazon is cheap enough to be able to put and measure the sub anywhere. At least then you'll know where works and where doesn't.

My guess though is that, with one sub, you'll move the null rather than remove it. You might get lucky, but filling nulls is the reason people go for more than one sub.
 
Upvote 1

benzi

Active Member
I would also try measuring the sub in different places in the room, even if they're not practical long term. A long subwoofer cable from amazon is cheap enough to be able to put and measure the sub anywhere. At least then you'll know where works and where doesn't.

My guess though is that, with one sub, you'll move the null rather than remove it. You might get lucky, but filling nulls is the reason people go for more than one sub.

Luckily I have 10m cable - I tried a number of positions across front wall with similar results. I should have got the UMIK sooner....would have saved some time and money changing subs looking for improvement etc.

Do you think dual subs is best way to get rid of the null?

Probably would have just kept my T5s 🤦 and maybe just added a bigger sub for HT. Well it's kept me entertained during lockdown ☺️
 
Upvote 0

Conrad

Moderator
Luckily I have 10m cable - I tried a number of positions across front wall with similar results. I should have got the UMIK sooner....would have saved some time and money changing subs looking for improvement etc.

Do you think dual subs is best way to get rid of the null?
It's only worthwhile if you can place a second sub somewhere that fills in the nulls in the existing sub response. If all positions have a null there, you'll have a null.

Definitely try the existing sub in other places.

Probably would have just kept my T5s 🤦 and maybe just added a bigger sub for HT. Well it's kept me entertained during lockdown ☺️
It wouldn't have helped if you'd put it in the same place. Any sub in that position will have a null where you have it. That's the room, not the sub.
 
Upvote 0

benzi

Active Member
Thanks Conrad - been moving sub and re-measuring..... unfortunately can't get to the left hand side of the room. Null was present in pretty much all locations ☹️. It was slightly better in some but not practical locations long term.
 
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Conrad

Moderator
Thanks Conrad - been moving sub and re-measuring..... unfortunately can't get to the left hand side of the room. Null was present in pretty much all locations ☹️. It was slightly better in some but not practical locations long term.
Interesting. If it's in all locations try raising and lowering the mic, it might be height related.
REW says it's a tangential mode which is caused by multiple boundaries, so it's reflection.

Keep trying some more places, move the mic if needs be, see if you can get rid of it at all. Try putting the sub very near to/below the mic.

Treatments might help a bit, but probably not a lot.
 
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nielsoc

Standard Member
I might have read past it, but have you set up a crossover in you Lyngdorf from sub to mains or are the mains playing full range?
 
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benzi

Active Member
I might have read past it, but have you set up a crossover in you Lyngdorf from sub to mains or are the mains playing full range?
Sorry for late reply - Covid got in the way. Sub was connected to Lyngdorf and crossover was set in Lyngdorf. Yamaha was outputting into Lyngdorf assuming L/R were full range.

This was distorting my measurements. I've re-run everything, removing the Lyngdorf from the system.
 
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benzi

Active Member
I've been reading more input to using REW etc and based on advice from @Conrad & @Gasp3621 (thank you both) - I re-ran all measurements - completely removed the Lyngdorf from setup for testing and had sub connected to Yamaha RXA3070 only.

I've used 5no. positions along the front wall - Left corner, Left speaker (1/4), Centre Speaker (1/2), Right Speaker (1/4) and Right corner. It was really interesting to see the difference in measurements across all five positions as well as the variance in output between the seats either side of the MLP. I'm going to need some time reading up on next steps etc.

If I'm interpreting the data correctly (big IF), I'm assuming that based on my latest measurements - putting dual subs below my L/R speakers would give a more even output and level out the nulls in my room?
Below Speakers.jpg
LR Corners.jpg
Sub Only - Front Wall Positions.jpg
 
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jzh10

Novice Member
Hi. Usually the best way to deal with room nulls is
  • move your seating position so you aren't sitting in the null (not always practical). Doesn't eliminate the null but moves it out of the way.
  • move the sub along the side wall so the null position changes (sometimes practical)
  • more than one sub, especially for home theatre - 4 is best, but even 2 works better than 1
 
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benzi

Active Member
Hi. Usually the best way to deal with room nulls is
  • move your seating position so you aren't sitting in the null (not always practical). Doesn't eliminate the null but moves it out of the way.
  • move the sub along the side wall so the null position changes (sometimes practical)
  • more than one sub, especially for home theatre - 4 is best, but even 2 works better than 1
Thank you for comment. I've been discussing with Conrad/Gasp - I'm definitely moving towards dual subs. Only question is whether to sell Rel and buy two other subs or buy a second Rel T9x.

Positive and negatives on both options. Just working through different scenarios.
 
Upvote 0

jzh10

Novice Member
Thank you for comment. I've been discussing with Conrad/Gasp - I'm definitely moving towards dual subs. Only question is whether to sell Rel and buy two other subs or buy a second Rel T9x.

Positive and negatives on both options. Just working through different scenarios.
There is usually more than one way to get it done!
4 work even better than 2. Another thing about subs is that you can use multiple smaller ones instead of a single larger one. Helps with the budget a bit.
Also, room treatments are great, they really help but they are not appropriate to deal with a null. Treatments generally are to absorb or break down an excess of energy. With a null, there already isn't enough energy at that point in the room.
We're a Lyngdorf/DALI dealer in Toronto, so don't hesitate to ask, happy to help.
 
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