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Discussion Starter · #1 ·
Hi All

I hope my clickbait title attracts enough attention to you guys.
I have assembled a pretty decent surround setup (I think) in my living room.
It is used for music, games, movies and tv shows.
Details:


In my working quarters Ive a 2.1 setup for music purposes only, with:


Now it all sounds above average of course, every visitor is blown away and leaves with a smile on their face.
BUT, the subwoofer in the living room is very 'fidgety', sounding full at times, rumbling the sofa in movies, games and shows while sounding paper thin on the next bass tone.
Crossovers on the receiver: 80 hz for all speakers, none for the sub, sub gain is set just before half way and set to LFE on the sub itself. This one faces the long wall of the room.
The smaller sub in the working quarters sounds more consistent overall, there are no crossovers set here and the sub is set to LFE. This one is in a cube shaped room.

Ive come up with some potential culprits :

  • room size and shape: the living room opens up to the kitchen and is definitely not cube shaped: 6 by 8 meters, 2.5 meter high without the kitchen space counted in;
  • sub placement: with the massiveness of this sub, crawling and placement becomes difficult, it is now placed next to the left front in a corner, next to an external heating element;
  • crossover issues: maybe a higher or lower crossover eliminates the boomyness , the paper thin thing is actually more bothering.

I want to place the sub in another corner, but with the wiring I can only choose 2 corners or place it behind my seating area and need 3 people to move it.
Maybe going wireless with the sub, which opens up way more options, is viable?
suggestions/tips?
I can provide pictures at a later point, if needed.
 

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Sounds like you frequency response (FR) is not flat - it has (significant?) peaks and nulls. The cheapest option is to move the sub around to different locations, re-calibrate your set-up and see (hear) if things sound better.

The more-practical (but more-costly) option is to purchase some measurement gear such as:
 

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Discussion Starter · #3 ·
Sounds like you frequency response (FR) is not flat - it has (significant?) peaks and nulls. The cheapest option is to move the sub around to different locations, re-calibrate your set-up and see (hear) if things sound better.

The more-practical (but more-costly) option is to purchase some measurement gear such as:
Thanks and indeed, I also suspect the FR is not flat at all.
I do have decent measuring equipment already and am going to do some measuring later today, will post it here later.
Also, I try to calibrate as much as possible myself instead of via auto calibration (which I tried and found unworthy :) )
Meanwhile a quick pic of the setup to see the subs positioning:
3048992
 

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Try doing the sub crawl. Just from the picture there are several other places you can put the sub, unless you don't want to move it for aesthetic reasons.
 

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Discussion Starter · #5 ·
Try doing the sub crawl. Just from the picture there are several other places you can put the sub, unless you don't want to move it for aesthetic reasons.
Ive been wanting to do this, but it takes time and effort and might want to wait with it , until I purchased a wireless sub adapter.
Aesthetics is not really a problem for me, but it adds;
First off I want to make sure if the subs placement is really that bad, below 2 screenshots of two separate tests of frequencies from 16hz to 150hz.
The yellow line should be checked for inconsistencies, Ive done a sweep and an incremental increase for every 5hz in the range.
From 20hz, I did notice it was producing waves, but did not hear them, cranking up the volume made something rattle in the kitchen and pressured the room.
From 35hz, it was fairly noticeable , from 40hz it was starting to be very present.
Most intriguing is the bump from 45hz uphill to 80-85hz, on which the crossovers are set.
So, from 30 to 40hz, a null?
And, from 70hz to 90hz, a peak?
I will need to investigate these frequencies a bit more, and maybe with even beter equipment.

3049006
3049007
 

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Based on your graphs, I wouldn't be trying to tune the sub or analyze the repspons above 100hz. To start, set the sub crossover on the Onkyo to 80z and then redo your sweeps. Change the graphs to logarithmic if possible and repost.
 

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Discussion Starter · #7 ·
Based on your graphs, I wouldn't be trying to tune the sub or analyze the repspons above 100hz. To start, set the sub crossover on the Onkyo to 80z and then redo your sweeps. Change the graphs to logarithmic if possible and repost.
Thanks for the response.
Any reason the logarithmic scale is better here?
Ive included 2 more test screenshots below. They seem consistent.
 

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Logarithmic is done as it shows all octaves in the same width, as octaves proceed in a logarithmic fashion. You also need to turn off smoothing so we can see the actual modes (see your last shot above). Finally, you need to change the scale of the DB, you have 20db increments which makes everything look smooth. It should be 5 db.

Just by looking at your second graph, I see a 20+db peak in your mains between 120-180hz. This is extremely large and will have the effect of masking lower bass frequencies.
 

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Discussion Starter · #9 ·
Logarithmic is done as it shows all octaves in the same width, as octaves proceed in a logarithmic fashion. You also need to turn off smoothing so we can see the actual modes (see your last shot above). Finally, you need to change the scale of the DB, you have 20db increments which makes everything look smooth. It should be 5 db.

Just by looking at your second graph, I see a 20+db peak in your mains between 120-180hz. This is extremely large and will have the effect of masking lower bass frequencies.
Ah did not know about the octaves, any reading material about this you might suggest?
Seems usefull when calibrating.

Redid test with another interface which allowed rescaling the db per 5db increments.
Also included screenshot of settings.
This one does paint a very different picture, coming close to being aĺl over the place.
Seems ive some work to do?



Edit: photo was not clear
3049046
 

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Ah did not know about the octaves, any reading material about this you might suggest?
Seems usefull when calibrating.

Redid test with another interface which allowed rescaling the db per 5db increments.
Also included screenshot of settings.
This one does paint a very different picture, coming close to being aĺl over the place.
Seems ive some work to do?



Edit: photo was not clear View attachment 3049046
Can barely see it (can see on an iPad, but not my fancy calibrated computer monitor). First, don't get alarmed, what you are seeing is perfectly normal. Virtually all domestic rooms have massive variations in the bass range. I am assuming the red line is your subwoofer only and you are allowing it to run full range for measuring, but using a crossover for listening. Most rooms have a large peak or suckout at about 40hz, I don't see that in your room which is good.

In looking at the owner's manual for your receiver, it appears that the default is a 100hz crossover. Please go and change all the crossover frequencies to 80hz and make sure that the subwoofer crossover is disabled or if unable to disable, set to the highest frequencies. While you are there, make sure your distance measurements are set properly on your speakers. Now run your sweeps and check the measurements and post back.

I am assuming you will still have a peak in the 70hz range, but it will likely be smaller. We can easily cut that peak later on, but first we need to get you baselined. That peak is masking the lower bass, which is why it will sound a bit tubby and really loud on some stuff and not on other.

Edit: I just went backed and looked at your original post. You need to set your receiver to have the sub at 80hz also and LFE at 80hz. For your secondary system, try setting the subwoofer crossover to 80hz.

Here is some good reading on subwoofer setup:


Finally, don't get to worried about the sub position right now. In most cases, the corner is a good placement for a single subwoofer. Your measurements (which are presumably at your listening position) show that you are getting a decent response, it looks like the primary issue is the lack of properly crossing over.
 

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Discussion Starter · #12 ·
Can barely see it (can see on an iPad, but not my fancy calibrated computer monitor). First, don't get alarmed, what you are seeing is perfectly normal. Virtually all domestic rooms have massive variations in the bass range. I am assuming the red line is your subwoofer only and you are allowing it to run full range for measuring, but using a crossover for listening. Most rooms have a large peak or suckout at about 40hz, I don't see that in your room which is good.

In looking at the owner's manual for your receiver, it appears that the default is a 100hz crossover. Please go and change all the crossover frequencies to 80hz and make sure that the subwoofer crossover is disabled or if unable to disable, set to the highest frequencies. While you are there, make sure your distance measurements are set properly on your speakers. Now run your sweeps and check the measurements and post back.

I am assuming you will still have a peak in the 70hz range, but it will likely be smaller. We can easily cut that peak later on, but first we need to get you baselined. That peak is masking the lower bass, which is why it will sound a bit tubby and really loud on some stuff and not on other.

Edit: I just went backed and looked at your original post. You need to set your receiver to have the sub at 80hz also and LFE at 80hz. For your secondary system, try setting the subwoofer crossover to 80hz.

Here is some good reading on subwoofer setup:


Finally, don't get to worried about the sub position right now. In most cases, the corner is a good placement for a single subwoofer. Your measurements (which are presumably at your listening position) show that you are getting a decent response, it looks like the primary issue is the lack of properly crossing over.
First of all, thanks for taking the time to analyse.

What I did is measure all frequencies between 0 and 150 hz at the MLP. Not only the sub, every speaker in the system. Coupled a tablet via 3.5mm jack into the receiver front and played a ten second sweep of these frequencies , thrice.

The red line you then see is the maximum measured db for every frequency in that range, of the three sweeps.

Some pics below of my settings on the receiver. I did not set any low pass filter for the sub on the avr. I could not figure out why this was needed when every other speaker had set a crossover.

Then the sub itself has some settings itself: gain and frequency filter, which goes from 120hz to LFE. Always has been on LFE. Gain always around halfway, sounding too boomy very quick, sounding very thin very quick when turned up or down.
Also a phase switch, 0 or 180. Always been 180 because it sounded way better that way.

Now how would one go about and dim the peak at 70hz, which supposedly shadows the lower frequencies? I really have no clue :'-)
 

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You need to enable LPF or LFE and set to 80hz. You are high passing your main and surround speakers (i.e. frequencies below 80hz are filtered out). If you do not enable a low pass filter for your subwoofer (i.e. filter out frequencies above 80hz), it will be overlapping with the mains, which will result in an uneven frequency response, likely part of the big bass peak you see, and trouble at higher frequencies as the subwoofer will break up depending on how it is designed to deal with frequencies above 150 hz or so.

One you have enabled the low pass for our subwoofer, start with your phase switch at 0 degrees. Do a sweep with your system configured as above and let us see.
 

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Discussion Starter · #14 ·
You need to enable LPF or LFE and set to 80hz. You are high passing your main and surround speakers (i.e. frequencies below 80hz are filtered out). If you do not enable a low pass filter for your subwoofer (i.e. filter out frequencies above 80hz), it will be overlapping with the mains, which will result in an uneven frequency response, likely part of the big bass peak you see, and trouble at higher frequencies as the subwoofer will break up depending on how it is designed to deal with frequencies above 150 hz or so.

One you have enabled the low pass for our subwoofer, start with your phase switch at 0 degrees. Do a sweep with your system configured as above and let us see.
Right, makes sense. now I have set the lfe crossover to 80 hz and did the same test, first with phase at 0, then again with phase at 180. Results look very similar to me, but one seems to have serious drops at frequencies above 100hz.

How do you analyse this graph, for this purpose?

3049150
3049151
 

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@CDMC2, I have always read that the LPF for LFE should be set at 120Hz, as the LFE channel has content that high.
OP, I noticed that it shows 6Ohm impedance for your speakers. I would set that to 8Ohms, if at all possible. Setting it lower actually puts a voltage limit on the amp in order to protect the circuitry (meaning, their rear ends).
A sub crawl definitely needs to be done. IMHO, the easiest way to do it is to plop the sub in your MLP playing frequency sweeps and crawl around the room with your SPL meter/measurement mike. Of course, getting another, identical sub will help even out the bass response throughout your room. The sub crawl is free, another sub is not... lol
 

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Discussion Starter · #16 ·
@CDMC2, I have always read that the LPF for LFE should be set at 120Hz, as the LFE channel has content that high.
OP, I noticed that it shows 6Ohm impedance for your speakers. I would set that to 8Ohms, if at all possible. Setting it lower actually puts a voltage limit on the amp in order to protect the circuitry (meaning, their rear ends).
A sub crawl definitely needs to be done. IMHO, the easiest way to do it is to plop the sub in your MLP playing frequency sweeps and crawl around the room with your SPL meter/measurement mike. Of course, getting another, identical sub will help even out the bass response throughout your room. The sub crawl is free, another sub is not... lol
going to try and set the low pass filter to 120hz. havent tried that before. exciting.

8ohms is not an option in the menu, 4 or 6. The manual saysto select 6 for 6 and above, 4 for the rest.

Sub crawl is definitely going to happen, soon. Already invited people to help out.
 

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Keep it where it is, then.
 

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going to try and set the low pass filter to 120hz. havent tried that before. exciting.

8ohms is not an option in the menu, 4 or 6. The manual saysto select 6 for 6 and above, 4 for the rest.

Sub crawl is definitely going to happen, soon. Already invited people to help out.
Be sure you have knee pads available for your guests. It's only right, as the host! :p
 

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Discussion Starter · #19 ·
Be sure you have knee pads available for your guests. It's only right, as the host! :p
It better be worth it, then ;) . But as is custom here, after the job is done, the host provides food, booze and entertainment.
 
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