Struggling with room treatment placement and possible problems.

[Flaesh]

It is quite obvious that the subwoofer(s) in Base layer speakers at 60db.mdat file have undergone room correction.

 

[JohnDykstra]

Welcome to ASR! You're not THE John Dykstra are you? The CGI John Dykstra?

unfortunately no, I don't have that bank account. But I'm a huge fan of his work, obviously. No relation to Lenny either, for the baseball nuts. Just a boring dude who's focus his attention on room acoustics. And records. And cats. Booze is cool too.

 

[No_hair_left]

Hey everyone. So I'm new here, please be gentle with me, I'm just getting the 'lay of the land' on this forum.

If I say anything out of line or without following forum protocol, please forgive me, I'll adjust quickly with guidance.

No hair left, your room graphs in REW actually look pretty decent. Far better than many untreated rooms that come across my desk. You don't have any dsp correction applied during these sweeps do you? The sub regions looks far more linear than I'd expect.

It would be great to see a 'left with subs' and 'right with subs' in the same capture, just to get a full picture of sound over time in one view.

Could you maybe post that for us? A full range sweep of left alone with subs and right alone with subs, and if there is any dsp correction currently in play, let's turn that off for now as well.

I did have dsp on for all of it after room correction, I thought I needed it on to see what can be improved after it's done its thing.

I am currently waiting for a new umik as mine stopped working yesterday so I'll re-measure everything with no xt32 applied.

 

[JohnDykstra]

No, you want to look at uncorrected values so we have the clearest view of what the actual problems are. DSP is a powerful tool, but the rotation of phase that occurs to get a flat looking curve lies to us in the _actual_ time domain situation of the room. Looking at the waterfall it's clear that there are going to be some 44 and 76hz resonances. It's ideal to see how long those are actually ringing without the influence of dsp phase rotation, because phase rotation or not: those frequencies are lingering longer than they should. That ideally is quelled, not just for the integrity of 44 and 76 hz, but all of the octave and harmonic regions upward from those fundamentals. Now, there's obviously also some resonance in the 20hz region, but you can't treat 20hz with bass traps. Rooms that are linear/controlled through 20hz are built, not treated.

 

[Bjorn]

Another thread that starts about RTx, invalid measurements for small room acoustics and no one can correct. What a sad development t and with less and less relationship to true science it seems.

What's next? Someone that will advice DSP for acoustic issues with no minimum phase behavior and from someone with practical no proper experience in the field?

 

[Pareto Pragmatic]

No, you want to look at uncorrected values so we have the clearest view of what the actual problems are.

Very true!

I did look at the measures. I do see a potential resonance issue at 20hz, so I would suggest for the sub to use a 512 sample and start the sweep at 15. That will get energy into whatever might be causing that resonance and get it up to full force by 20hz. If the small peak at 20 gets bigger, resonance issue. I suspect the left wall, interior walls are often hollow. If the peak at 20 doesn't move, no worries on this.

Beyond that, the room is a problem, with lots of reflections. The sub placement gives good response (post correction) but firing them to maximize reflections in the front of the room is likely one part of the long decay issue. Pointing them into the room, with a slight angle in towards the couch, will help on that issue, but likely cause you other problems.

More of a corner placement on the subs will give you reinforcement of bass you seem to want. Maybe, since these were post correction, you don't need as much as you have right now?

A couple of book cases left and right, with the shelves NOT full but with lots of irregularities in what is in it, that's an idea you should consider. Something dark might help a bit with reflections from the white walls and improve picture a bit.

If you are open to it, ceiling treatment can help (basically an absorber hung with an air gap above it). Most people don't want to go that route, but with a few hooks it is an easy DIY. A bit of treatment on the tv wall can't hurt.

Opening doors can help, including kitchen cabinets. Doors at angles will redirect sound. Inside closets and cabinets will eat some reflections.

I would start with free things, before thinking treatment. Try subs pointing out (but not straight out), try opening doors. See what happens. Then decide what you need to do to get things to a level you can live with.

 

[Pareto Pragmatic]

Another thread that starts about RTx, invalid measurements for small room acoustics and no one can correct. What a sad development t and with less and less relationship to true science it seems

Yeah, why can't people who don't know a lot start sensible science based threads?!?!?

Ignorance + a desire to learn is a good thing. The OP clearly wants to measure and improve things, but just lacks the LARGE amount of knowledge that goes into doing that right. So my approach (as a very much non-expert but not newb) is to nudge them in the (hopefully) right direction. If you had just posted a link to information on WHY RTx is bad for small rooms, that would have helped the OP learn something. Moved them further along the path of learning.

Anyone who wants to measure, believes in measurements, and is trying to do the right thing... that should be encouraged as much as possible. That's my take on such posts.

I do get the frustration, I have done time on forums where I am an expert, and seeing the same thing over and over again gets old and frustrating. Annoying. Do a search people!!!

But I do try to keep in mind these questions, when authentic, are from people who are trying. If they try, I will try too.

 

[No_hair_left]

I don't know what RTx is lol

I'll have to wait for my new mic but once I get it i'll get some uncorrected measurements of everything.

I'll have a bit more of a play with the subs too as I never thought of angling them towards the mlp, when I fire them into the room the frequency response is none existent after 80hz, I did try different variations of 1 firing at wall and 1 into the room but again I couldn't get anything usable after 80hz, played with the phase of both of them on the app too.

 

[Keith_W]

I don't know what RTx is lol

It refers to the "Reverberation Time" family of measurements - RT60, T30, T60, Topt, etc.