A disastrous subwoofer journey

[prateekatasniya]

But Why? The subs are 2 different locations interacting with different aspects of the room. They need to be EQed separately.

MaSh

Correct..

 

[square_wave]

I am not a subwoofer user but I have seen/watched how people in high end audio use subwoofers. If the room is relatively small - room treatment is a big part of the equation. Even when you introduce a single capable sub woofer in the room, there is bunch of treatment and positioning activity ones needs to painstakingly go through before one can even understand what is going on. After all that is done, there will not be any bass cancellation at your listening position. The next step is adding one more sub woofer. This is tricky business. If done right, it will smoothen out the bass even further and bring refinement and increase the bass output making the bass even more enjoyable. But, the first step is to get bass enjoyable in the room with a single subwoofer. If you just keep adding subs without solving the first problem, you will just add to the confusion.

Eventually you may be able to get this sorted out by DSP, EQ etc... but that is a different journey altogether. Sometimes less it better.

 

[liverpool_for_life]

Correct..

What? Is your recommendation to EQ each sub individually, without the other one playing at all?

 

[sandeepmohan]

You should write to Rythmik about your experience and present those graphs and ask them what might be going on. They might point or guide you in a direction none of us can.

I can only think of input sensitivity issues, swapping sub's between receiver pre outs and running one at a time or one or the other and see what it does to the sound.

I hope you have tried a couple of other sources, movie tracks to check if the results are all the same.

To me, this sounds like an issue with the room. I have experienced such behavior in stereo configuration where a pair of speakers sound vastly different in their bass output to the point where I thought I bought the wrong speaker. In my case, it was a 15k PSB speaker sounding better than a 200k speaker so quite scary.

 

[Love4sound]

Eventually you may be able to get this sorted out by DSP, EQ etc... but that is a different journey altogether. Sometimes less it better.

I am using a mini dsp

You should write to Rythmik about your experience and present those graphs and ask them what might be going on. They might point or guide you in a direction none of us can.

I can only think of input sensitivity issues, swapping sub's between receiver pre outs and running one at a time or one or the other and see what it does to the sound.

I hope you have tried a couple of other sources, movie tracks to check if the results are all the same.

To me, this sounds like an issue with the room. I have experienced such behavior in stereo configuration where a pair of speakers sound vastly different in their bass output to the point where I thought I bought the wrong speaker. In my case, it was a 15k PSB speaker sounding better than a 200k speaker so quite scary.

Yeah played all the heavy action sequences that I regularly use to test subs. I have got many inputs by other fm’s which I need to experiment first. Another weird thing I noticed which I need to test and confirm.This might be some bug in my chain which I can only figure out by taking my gears to another fm house who has the same avr, nvidia shield pro 2019 and have a dual sub set up with mini dsp. Like I have mentioned before rear sub had excellent bass and punch in the terminator scene. I played various scenes like those for hours and shut down my system and for 3 days I never touched anything or made any changes. So when I watched the same scenes after 3 days the bass was not there and it was flat in the same scenes I tested 3 days back. I know it sounds weird but something is not just right and I don’t think it’s only the room. I am just chasing bass that I have experienced in my room with single and dual subs before. I have done various dual sub tests in my room before pulling the trigger. I have even successfully integrated a xtz 500 watts 12.17 with a 50 watts 6 inch Yamaha sub.

 

[sandeepmohan]

Don't get me wrong.
From what I see in those images, that is a lot of speakers (and low frequency) in a room which isn't that big.
Also, any sub woofer placed in that right corner is going to sound a whole lot better than the one on the left.
All you've got left to do is to measure the pre amp output voltage from your avr. You'll need a multi meter for that.
You should also be getting rid of those glass supports for those compact speakers. They are a no-go for sound.
What are you using a mini dsp for?
Good luck

 

[Love4sound]

Don't get me wrong.
From what I see in those images, that is a lot of speakers (and low frequency) in a room which isn't that big.
Also, any sub woofer placed in that right corner is going to sound a whole lot better than the one on the left.
All you've got left to do is to measure the pre amp output voltage from your avr. You'll need a multi meter for that.
You should also be getting rid of those glass supports for those compact speakers. They are a no-go for sound.
What are you using a mini dsp for?
Good luck

Yeah I know glass supports are not ideal but I can’t place speakers on mounts. There is no space for mounts and also with a 2 year old running around I don’t want to use stands.Mini dsp I am using for eq and integrating both subs. And yeah lot of speakers but they blended well.

 

[Thirumalkumaran]

I am using a mini dsp

Yeah played all the heavy action sequences that I regularly use to test subs. I have got many inputs by other fm’s which I need to experiment first. Another weird thing I noticed which I need to test and confirm.This might be some bug in my chain which I can only figure out by taking my gears to another fm house who has the same avr, nvidia shield pro 2019 and have a dual sub set up with mini dsp. Like I have mentioned before rear sub had excellent bass and punch in the terminator scene. I played various scenes like those for hours and shut down my system and for 3 days I never touched anything or made any changes. So when I watched the same scenes after 3 days the bass was not there and it was flat in the same scenes I tested 3 days back. I know it sounds weird but something is not just right and I don’t think it’s only the room. I am just chasing bass that I have experienced in my room with single and dual subs before. I have done various dual sub tests in my room before pulling the trigger. I have even successfully integrated a xtz 500 watts 12.17 with a 50 watts 6 inch Yamaha sub.

Might be late to the discussion, but why did you needed a second sub?
Did you lose SPL?, or is the bass was localised?
Looking at the coverage volume, even a single 12 would be enough. Kindly share your room details and rough sketch for it!

 

[Love4sound]

Might be late to the discussion, but why did you needed a second sub?
Did you lose SPL?, or is the bass was localised?
Looking at the coverage volume, even a single 12 would be enough. Kindly share your room details and rough sketch for it!

Many scenes sound flat and no bass. It’s like subwoofer is off. Shared room pics along with pure direct single sub graph at front right position

 

[Kannan]

Instead of positioning the subs diagonally opposite, why not put them parallel to one another either on the front or on the rear.

 

[Love4sound]

Instead of positioning the subs diagonally opposite, why not put them parallel to one another either on the front or on the rear.

Sure Kannan I can test that as well. Many suggestions shared and for me to check all that will take a months time for sure. I can’t do the tests continuously as I need to be easy with my recovering ears

 

[chander]

A quick question for @love for sound - right next to the AC you have two speakers (perhaps full range) - that look like subs too, what are those?

 

[Love4sound]

A quick question for @love for sound - right next to the AC you have two speakers (perhaps full range) - that look like subs too, what are those?

They are in-ceiling speakers. Monoprice 8 inch

 

[srinisundar]

Yeah the thought came in mind and if I got a sealed sub would have been easy to place them in the ceiling. This one is to heavy and would be difficult to place them.

Yes of course current sub will be heavy. Try ceiling sub-woofers specifically made for ceiling.. May be some dealers will have demo piece and can try that in your home if they agree.

 

[Love4sound]

Yes of course current sub will be heavy. Try ceiling sub-woofers specifically made for ceiling.. May be some dealers will have demo piece and can try that in your home if they agree.

Hahah more experiment. Well I want to go the easy route. Will try to see if I can some how calibrate the existing subs. If I fail then i will just sell one and settle using one sub. Still have many options left to experiment

 

[Thirumalkumaran]

Instead of positioning the subs diagonally opposite, why not put them parallel to one another either on the front or on the rear.

this.. should be tried 1st.. mine is 17x22ft, and it works well keeping in the same wall/plane as the front speakers. Infact symmetrical sounded better than asymmetrical (Textbook suggestion) for me!

 

[Love4sound]

this.. should be tried 1st.. mine is 17x22ft, and it works well keeping in the same wall/plane as the front speakers. Infact symmetrical sounded better than asymmetrical (Textbook suggestion) for me!

Ok I never knew we can try parallel placement. Normally all place two at front or diagonally opposite so this thought never came across my mind.

 

[MaSh]

Because what you hear is the result of how the two subwoofers combine in your room at your listening position, that's why.

Correct, but by not correcting them individually first they are just going to cut each other off and give the listener a null exactly what's happening here.

MaSh

 

[RajithKumar]

Yeah thanks for the visit. Placement is the main concern here as I have only front right and rear left options and worked very well with other subs. Many suggestions have poured in and guess I will take some time to experiment them and confirm. For now I switched back to one sub and quite liking the experience.

U can try placing subs on Loft too.
If one sub satisfies ,then keep one and sell tbe other.

 

[Love4sound]

So today I thought of starting off from the easy experiments others suggested. First as mash suggested I tried individual eq and it didn’t work out. Next I tried as per Liverpool4life suggested and added delay to the front sub. So please find the results in the images below.
1st-Pure direct graph of front sub
2nd-Pure direct graph of second
3rd-Pure direct of both subs with no delays
4th- Has two response.The top is the best result of adding delays to front sub. Bottom is the best result of adding delays to the rear sub. From this graph I feel the response when delay is added to the front sub is better.
5th-Best results from applying eq individually as mash suggested
6th-Has two graphs where both are after EQ applied using mini dsp. Top response is the result of adding delay to front sub and the bottom green graph is the result of adding delays to the rear sub