Is it possible to get better bass in my room or do I need to change speakers?

Nuprin

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I really do love the sound of my EA Micro Ones. Huge soundstage, great detail, imaging and smooth highs for my ears. However, in my current room I have a significant 20-30 db drop in the 100-110hz range, depending on where they are placed in my 17'w x 13'D x 10'H. There are modest amounts of acoustic treatment on the front and side walls. They are paired with 2 sealed subs along the 17'w wall, about 9.5ft apart and I sit nearfield at 9' from the tweeters.

In my previous home, in a different shaped and size room, the bass was great so I know that the speakers are capable in that 100-110hz range. I have tried moving the speakers everywhere trying to find a good position that allows for a smooth bass response, alas there must be some cancellation in the room that's causing such a huge drop. Now, when I measured the response of another pair of speakers, small towers with a transmission line design - so ported out of the bottom, the drop at the 100hz was "only" about 16db as you can see below in the green line vs the Micro Ones in the brown line. Yes, there is a 10db bump at the 40hz that I need to address with some trapping or possibly a crossover like the JL CR1. I'm left to think that because the Micro Ones are rear ported, I may have better results going with another speaker design that is NOT rear ported or can be placed closer to the wall since I sit in the room that's only 13' deep.

Front Ported or Sealed Design - Magico A3/A5? Something like Audio Note, which were designed to be placed near the wall/corner? Omni directional speakers? Of course I don't want to give up the rest of the performance of the Micro Ones. I heard the Walsh Omnis and they were not even close to being in the same league in terms of refinement. Considering I may be stuck in this room for quite a while, I'm open to various suggestions and budget ranges.

10.07.21.jpg
 

ecwl

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Mar 20, 2021
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I’m wondering if your speakers are symmetrically setup in the room or not. If you just measure just one speaker, do you still have the same -10dB dip?

moreover, do you have the ability to move your listening position forward or backward? If so, you may want to see if you get a better bass response from a new seating position.
 

Nuprin

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Virtually identical when measuring each channel, within 2db anywhere on the graph.

I tried the speakers on the 13' wide wall and found them better on the 17' wall - also because of where the windows/doors are and placement of my desk in the room. The reason I say there must be some type of cancellation happening is because the middle of the room, or if you drew a smaller rectangle 10'x7' inside the larger 17' x 13' rectangle, there is virtually NO bass. It's a 40-50db drop in the middle of the room. The bass only exists about 3.5' from each wall so I sit just under 3' from the back wall, which I've placed a bookshelf directly behind. There is still a bit too much reverb I need to tame in the middle and upper frequencies but I believe the bass needs to be solved first.
 

sbnx

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Mar 28, 2017
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What is the distance from the tweeter to the wall behind the speaker?

can you smooth the data to 1/24th octave and zoom in to 20 -300Hz?

thanks
 

Tim Link

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I suspect the 100Hz suck out might be a ceiling bounce issue. I calculate the ceiling bounce to be about 6 feet delayed from the direct sound from the speaker, which is about 1/2 the 100Hz wavelength. That would explain why the dip persists regardless of placement.
 

Nuprin

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Distance to the tweeter from back wall is 40". I'll have to re-measure as it was just a saved screen shot I took.

Spoke with some at JL audio about their CR-1 Crossover. They believe there's some type of phase cancellation - the wave from the port reflecting to the listening position is possibly causing the null(s) at the listening position/middle of the room. They then suggested plugging the ports on the speakers and going through a series of tests utilizing the CR-1, crossing high around 95hz and adjusting the phase control on the sub(s). It also has damping knobs that you could bump up or down the response around the crossover point to a certain degree for both the signal sent sub and speakers.

This is starting to get complicated and I'm not sure if my issues can be solved with a crossover/change to or getting different speakers, or software EQ/room correction (which in my past experience has not been great), or it's a room acoustic treatment issue.
 

Nuprin

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I suspect the 100Hz suck out might be a ceiling bounce issue. I calculate the ceiling bounce to be about 6 feet delayed from the direct sound from the speaker, which is about 1/2 the 100Hz wavelength. That would explain why the dip persists regardless of placement.
Is there any way to test this without having to attach something to the ceiling? In my previous room/home the ceiling was only 8' in stead of 10' but there was an opening to the left and back right, plus an angled wall on the back left. It had a few peaks but no suck out at 100hz.
 

sbnx

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Nuprin,

I have attached photos of what is happening in your room that is affecting the frequency response. Assuming your ear height is 36" and the speaker height is 36" and you have a 10 foot ceiling and you are sitting 9 feet from the speaker then I calculate the ceiling bounce at about 75Hz. There are two competing phenomenon -- Room mode excitation and cancellation due to SBIR (Allison effect). You have a pretty severe dip between 70 and 110Hz. This is going to make the bass sound super lean with very limited dynamics. (Probably nothing you don't already know). The port is definitely producing out of phase sound centered at the tuning frequency that will change how the speaker interacts with the front wall (Behind the speaker). If you want to see what causes each dip then you can measure where they stand. Move them back 6" then forward 6" then left 6" and then right 6". This will show you which dip is caused by moving in each direction but doesn't really change how you fix it.

A note on larger speakers -- the larger woofers in these speakers will excite the room modes more and will not fix the nulls.

You have two options:

The first option is to find the listening position with the smoothest bass and then position your speakers to further smooth the response. Since you have REW you have the tools to do this. Use the RTA along with the pink noise signal generator. Set it to 1/3 or 1/6 octave from 30 to 200Hz and move the mic back and forth to find a spot where the RTA looks the smoothest. Sit in this location. Then position your speakers to fine tune this. You should be able to find a spot the smooths out the response. If you add some absorbers you can "catch" the 100Hz dip. this is well within the range of acoustic absorbers. I would get a four GIK monster bass traps to experiment with.

The second option is to do the first option then use the CR-1 and subs to smooth the bass below 80Hz. The CR-1 offers a ton of flexibility in sub setup. (what kind of subs do you have?). If you use the CR-1 and you integrate the subs well then you can get ruler flat frequency response up to 80Hz. I will paste and example in another post.
 

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Nuprin

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Tweeter on the speakers are 40" high with the listening position about 38"-39". Speakers have 4" drivers arranged in an MTM configuration.

The subs are Seaton Sound Submersive HP+ (15" sealed opposing woofers") - I have two of these, plus a single slave that can be driven from one of the other amped HP+ units (but cannot be run as stereo). I also have their 12" sub as well.

Currently in the listening room I'm using the single 15" HP+ and the 12" version - just to try different variations. The other 15" HP+ is in the surround sound system running with it's slave. So I have the ability to run a single sub, two powered subs in stereo or two subs running mono with one of them as a slave driven unit.

I have been considering trying some of the GIK bass absorbers - just not sure if the Soffit, Monster or Tri-Trap is better and to go with the range limiter version or not? https://www.gikacoustics.com/product-category/bass-traps/

Crossing over the speakers at, say 80hz should improve overall sound with less demand on the smaller drivers of the speakers would be my assumption. After adding a couch into the room along with some drapes to cover two French doors, it did improve the 100hz dip by about 5db. I'm just not sure if I can make up that huge of a difference with acoustic treatment. Really would prefer not to have to hang stuff on the ceiling if possible.
 

sbnx

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Here is one example of what I mean by integrating the subs.

I set up a room at LSAF (Lone Star Audio Fest) in 2019 using a pair of Vivid V1.5's and a pair of JL Audio F113's. I used the CR-1 crossover and a DSP to control the subs. Note the scale on the frequency response graph is in 2 dB increments. So the bass is basically +/- 2 dB from 20Hz to 20kHz. (The smoothing is 1/24th octave) The sound in this little hotel room was pretty phenomenal. Not too much acoustic treatment -- the real traps diffusers behind the speakers, a pair of 13" ASC tube traps in the corners and there was a 2" panel on the wall behind the listener. This stuff pretty much treated above 100Hz.

One tip on using the CR-1 and subs. If you are going to cross over at 80Hz then you need to get the speakers at least 3.5' from the wall.

For GIK...Get the monster traps for the side walls. The soffit would be great as it is out of the way (up in the ceiling corner) and would serve to reduce overall broad band modal ringing quite a bit.
 

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Nuprin

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One tip on using the CR-1 and subs. If you are going to cross over at 80Hz then you need to get the speakers at least 3.5' from the wall.

The speakers are just about at that distance. If I cross over at a lower frequency, does that mean the speakers can go further back or the opposite?
 

sbnx

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As you move the speakers away from the wall the null will move down in frequency. The idea here is that you want the null caused by the speakers to be in the range of the subwoofer. (Or another way of saying that is you want the null from the speakers to be below the crossover point.) So...

If you move the speakers farther from the wall you can lower the crossover point. If you move the speakers closer to the wall you will raise the crossover point. A speaker distance of 3.5' will produce an SBIR dip at about 80Hz. In the picture of the vivids the distance to the woofer was a little over 3.5' maybe closer to 3.75'.

To fix the 100Hz dip you need to find the best listening position first. If you are going to use the subs as I mentioned above you don't have to worry a whole lot about what happens below the crossover point (say 80Hz).

On another note there is another way to do this using distributed subs. aka swarm or Geddes method. I have tried this before and got somewhat mixed results. I mention this as you have a lot of subs to use. The upside is that you don't have to use the CR-1. In your situation I think I like the CR-1 idea better as your speakers are small and will benefit from not having to produce output below the crossover point.
 

sbnx

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Is there any way to test this without having to attach something to the ceiling? In my previous room/home the ceiling was only 8' in stead of 10' but there was an opening to the left and back right, plus an angled wall on the back left. It had a few peaks but no suck out at 100hz.

There is a way to test this. Raise the speakers up a 12"- 18" and measure the frequency response again. You only have to sweep from 20-300Hz. See which dip moved. When you raise the speaker be careful to leave it in the same X,Y position.
 

Jim Smith

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The idea that the speakers can be closer to the rear wall can work, but it does affect Presence. I cannot imagine any recording engineer recording a musician or vocalist that close to the wall. Why do we think our loudspeakers can work where no performer could be at their best??
 
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Atmasphere

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Virtually identical when measuring each channel, within 2db anywhere on the graph.

I tried the speakers on the 13' wide wall and found them better on the 17' wall - also because of where the windows/doors are and placement of my desk in the room. The reason I say there must be some type of cancellation happening is because the middle of the room, or if you drew a smaller rectangle 10'x7' inside the larger 17' x 13' rectangle, there is virtually NO bass. It's a 40-50db drop in the middle of the room. The bass only exists about 3.5' from each wall so I sit just under 3' from the back wall, which I've placed a bookshelf directly behind. There is still a bit too much reverb I need to tame in the middle and upper frequencies but I believe the bass needs to be solved first.
This is classic standing wave behavior. You're not going to fix this with bass traps- to do that the traps would have to move dynamically about the room :)

What you need to do is break up the standing waves. I would take @sbnx 's advice and try to move your speakers a bit to see if you can reduce the frequency of the cancellation. IME though, you'd want to move the speakers closer to the rear wall (resulting in nulls where the wavelength is longer). Once that is done I would consider adding a pair of subs asymmetrically placed in the room, perhaps one in the rear and one to one side. You might have to play with the phase of one or both, and they should not be active above 80Hz so as to not attract attention to themselves.

This will be a lot trickier if the null persists above 80Hz! For that reason alone though, I'd place the speakers out from the short wall rather than the long one. That way the wavelengths can be longer before they reflect off of the wall behind the listener. My space is a similar size so I know this setup works. BTW unless your speakers have rear-firing information you can have them only a foot or two from the wall behind them without ill effects.
 

Nuprin

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Tested the frequency response with speakers 14" higher and the results were worse. Already tried placing the speakers along the 13' width side but had poor results there before but can revisit - I had to sit almost at the rear wall to get any bass and that puts me right in front of doors. I think I had them out as far as 1/3 of the way along the longer length before and still had poor results.

It is much preferred to sit along the 17' wall instead of the 13' as where doors/windows/furniture/desk locations are but I will do some testing to see any changes. Where they sit is about the best reading I can get out of them along the 17' wall or in the room from all the measurements I've taken so far.

If ceiling height is the issue or part of the issue, then I'm not sure if moving the speakers to the other wall will be better.

Currently there is one sub in the front left of the left channel speaker and one to the right of my seating position, but have moved them around a bunch of places already. Even tried 3 subs. Generally no huge differences unless the subs are in a position where they're cancelling each other so ceiling height could a culprit...
 

sbnx

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Can you publish your REW data with the speakers 14" higher? Compare before/after from 20-300Hz.
 

tkoslek

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Have you read or looked at the Swarm by AudioKinesis? Essentially it requires more boxes but in a troublesome room, I think it would solve the node problem it seems like you are having. I'm in a much larger room and not only do they fill in the bass side of things, integrating them also helped the imaging and mids/highs shine through.
 
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audiobomber

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Have you tried blocking the monitor ports? I don't like subs with ported mains due to phase issues. A sealed cabinet (or ported cabinet with blocked ports) would necessitate a 2nd-order Butterworth low pass filter on the subs, and reversed polarity. Along with REW Auto-EQ, I am confident this method would resolve your FR issue.

I use the above setup with a miniDSP crossover on the subs only. First I implement REW Auto-EQ filters on the right channel (monitor and sub) alone, then on the left channel alone. I repeat Auto-EQ with the entire system running. Then I add any additional EQ filters manually.
 

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