Bass modes, nulls, voids, peaks, valleys and massive frustration

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David60

  • Jr. Member
  • Posts: 9
You should be able to make this work. Try 62% back from the front wall for a seating position so you are not in a null in the center of the room. The advice given is sound. Take measurements every 6 inches and you may find a nice compromise location. I moved my seat farther back to avoid some build-ups than the math said I should but the REW told me differently and it worked. Keep experimenting. I used tape on the floor and the walls and a camera tripod to incrementally move the mic for each measurement.

Yes, will continue to brainstorm and tweak. I'm currently sitting at 53% of room length. A bit less and a bit more and the "bass tsunami" is much less evident. However, not being single has both advantages and disadvantages...although after 31 years of marriage the "advantage column" is not as convincing as it once was. Therefore I have to tweak secretly in the middle of the night disguised as a burglar. This hobby has all kinds of surprises over a lifetime. Brgds.

sarora9

I'll chip in with things others have not mentioned.

Possibly your significant other is not as dogmatic as you think. I speak from experience. I was allowed to place my Spatial X3s in a  favorable location ---this involved significant furniture shifting which she helped with---and 4 feet away from the front wall. I promised to  slide the speakers closer to the wall (by putting teflon furniture sliders under the feet) whenever we have guests over, which doesn't happen more than once a fortnight.

At the end she realized that she slightly prefered the new configuration of the room, with a some open space and some diagonals introduced.

I am in audio heaven and she agrees too that the sound now is awesome.





David60

  • Jr. Member
  • Posts: 9
Don’t give up just yet! I’ve moved my speakers many times over the 51/2 years I’ve owned them trying to optimize their sound in my problematic room. It can be a long process and also a great learning experience. Regardless of what recommendations GIK made, I would still experiment with bass traps, starting in the corners behind your speakers where you said there is a lot of bass gain. They provided the largest single improvement in smoothing out the bass response in my situation. Next was experimenting with positioning. Regarding the port plugs, I initially had the same experience as you; ports plugged on both speakers killed the bass but plugging only one speaker’s port eliminated much of the bass boom while still providing plenty of bass. I finally found the best spot in my room where the bass response is smooth, deep and tight and no port plug is used. It is a game of inches. The article below has lots of great information and was posted in another circle. Read the whole article, not just the section on bass traps.

https://ethanwiner.com/acoustics.html#bass%20traps

Yes, thanks again for the encouragement. Radio Paradise streaming now through the Naim equipment on the unplugged Sopras is a good listen at modest volume. Will keep trying indeed as I want to tri-trap the 2 front L/R   corners and find a way to adjust the TV and equipment rack positions.

Below we see the plugged/unplugged effect as measured from my listening position:



Red is unplugged and Green is both speakers plugged. One speaker plugged (not shown) is somewhere in between but I'm worried about the imbalanced impedance load that this would present to the amplifier...and it just seems a bit strange to plug just one speaker. I haven't given up yet. Brgds.

Tyson

  • Full Member
  • Posts: 11111
  • Audio - It's all a big fake.
Well if you are going to stick with box speakers, I'll give you some tips from when I was doing box speakers and EQ.  First, if you can do bass traps, then those are the most effective in dealing with bass humps as well as dealing with the bass causing the room to ring. 

Don't dismiss a swarm set of subs just yet, if you DIY them then you can make them to match your decor.

For now, the best thing to do is measure each speaker individually using RCA shorting plugs like these:

https://www.amazon.com/Shielded-Shorting-Filter-Noise-Canceling/dp/B01N0LNTTX/ref=sr_1_5?dchild=1&keywords=rca+shorting+plugs&qid=1625505255&sr=8-5

Plug one in to one side of your amp and keep your regular RCA cable plugged in to the other side.  Only one speaker will produce noise now.  Measure, then switch the shorting plug to the other channel and measure the 2nd channel.

Compare the 2 measurements.  You will notice that some peaks are the same from speaker to speaker but others peaks are different.  The ones that are the same, you can use the EQ for both speakers at a time.  For the humps that are unique to a particular speaker, EQ only that speaker to deal with them.

Other tips for EQ.  Start with the humps that are lowest in the bass and work upwards.  Because some of your higher level humps (and nulls) might be result of the things happening lower down.  Also, only use 'cuts' in your EQ, never ever use 'boosts'.  It's much better to drop bass humps and leave the bass nulls alone. 

David60

  • Jr. Member
  • Posts: 9
Well if you are going to stick with box speakers, I'll give you some tips from when I was doing box speakers and EQ.  First, if you can do bass traps, then those are the most effective in dealing with bass humps as well as dealing with the bass causing the room to ring. 

Don't dismiss a swarm set of subs just yet, if you DIY them then you can make them to match your decor.

For now, the best thing to do is measure each speaker individually using RCA shorting plugs like these:

https://www.amazon.com/Shielded-Shorting-Filter-Noise-Canceling/dp/B01N0LNTTX/ref=sr_1_5?dchild=1&keywords=rca+shorting+plugs&qid=1625505255&sr=8-5

Plug one in to one side of your amp and keep your regular RCA cable plugged in to the other side.  Only one speaker will produce noise now.  Measure, then switch the shorting plug to the other channel and measure the 2nd channel.

Compare the 2 measurements.  You will notice that some peaks are the same from speaker to speaker but others peaks are different.  The ones that are the same, you can use the EQ for both speakers at a time.  For the humps that are unique to a particular speaker, EQ only that speaker to deal with them.

Other tips for EQ.  Start with the humps that are lowest in the bass and work upwards.  Because some of your higher level humps (and nulls) might be result of the things happening lower down.  Also, only use 'cuts' in your EQ, never ever use 'boosts'.  It's much better to drop bass humps and leave the bass nulls alone.

Thanks for the tips. For the moment, yes, box speakers as I had a wonderful time with Magnepan and Martin Logan when I was younger, now I'm less inclined to fight with the refrigerator sized transducers. Best luck I ever has was/is with Sonus Faber, of which I still have two pairs at home, the oldest being 23 years old...
Very interested in the OB implementations but these days my room is the limiting factor. Yes, agreed, I wouldn't attempt to boost a null in EQ. Thanks again. Brgds.