Help me with understanding where to go with treatment and sub integration from here.

Powermankw

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So.... After a bit of a journey from headphones and office to taking over basement for 2ch listening room, I've done quite a bit of work. I covered my half basement (as much as I could), kind of irregular room with R-38 insulation, and 12 panels of 4" mineral wool. I could do more possibly, but I'm not sure it would be more beneficial. I've treated a lot of treble reflections, and I can't really go thicker anywhere to treat lower sub base. But I don't know for sure.

At this point, I'm really trying to get the best out of what I have. I took before and after measurements. I'm trying to find best placement and integration for Sub. I don't do and DSP and would prefer not to. However, on my Pi4 Mercury streamer I use Volumio, Gentooplayer, and audirvana so I can certainly use a DSP plughin on any of those platforms.

My room is definitely dead. The reflections I do show are from floor and chair. 25ms is back wall. But I am definitely a REW rookie. I would really appriciate if you could take a look at what I have and tell me what you think. The first is measures of all speakers and seperate. .. I goofed and didn't get a right speaker. I also played around with moving sub on front wall left middle and right to see what it looked like.

Thank you for looking.
 

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Powermankw

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So phase was causing huge issues with cancelling base. It really screwed up nearfield. Now that phase is correct, nearfield is really good. So then it was on to subs.

I played around with every possible location for my sub today. There is a massive null at 30hz, and the bad thing is there seems to be nowhere in my room it goes away. I don't get it. Once I located an OK place, I started playing around with tuning. There was a lot of things that made it even worse. Of course EQ does not fix nulls. I changed crossover frequency, phase, volume... finally I tried different crossover slopes, and low and behold... 6db fixed a lot. Checked different locations... I found a reasonable one that does well, frequency response is pretty good.

Now that is good, tried nearfield... there is literally no good place for my sub nearfield. It all looked horrible. Finally concluded that it is out for now... however, my FR nearfield with no sub is really good. Explains a lot.

There are still really big nulls at 300hz. Big peak at 600hz. (normal position not nearfield.)I do not know what to do or if anything can be done. I can play around with EQ, but I was hoping to not have to use any EQ... I like it clean.

Any suggestions?
 

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Powermankw

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Nothing?

So if this is only official support for technical issues, can someone point me to the use forum?
 

John Mulcahy

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The measurements look pretty good. The dip at 300 Hz is narrow and not likely to be an issue, the bump around 600 Hz doesn't look to be much of an issue either. Bear in mind that reflections from surfaces near the mic also cause peaks and dips in the response.
 

Powermankw

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Thank you! How wide does a null have to be to be audible... I know it's not exact, I'm just asking when does dips become a problem?

Also, I'm not really getting phase. (I know what it is) I'm talking about reading the measurement as a function of frequency. I'm trying to match speakers to sub... But both go is opposite directions. And when frequency is thrown I, I'm not getting how you Mach sub phase to speakers.
 

thothsong

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One thing to check is how the null aligns with fundamental frequencies of music notes. D4 is 293.6648 Hz, which is very close to the bottom of your Left null.
 

Powermankw

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One thing to check is how the null aligns with fundamental frequencies of music notes. D4 is 293.6648 Hz, which is very close to the bottom of your Left null.
I'm clueless what that means if it does.

One thing is for sub base, it requires thick traps which I can't do. But for the 12-16" of fluffy I do have, I figured that would be enough for the rest. So I'm suprised I still have issues above 100hz.

20221114 165942
20221114 165854
20221106 150112
 

thothsong

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I'm clueless what that means if it does.
It would mean that particular note in music would come out with reduced SPL for its fundamental tone. By way of reference, it's the D string on a violin.
 
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John Mulcahy

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You can match sub to mains using the Alignment tool in the All SPL graph controls to work out the delay required to get a good phase match between sub and main. There are a few threads on that, this is a currently active one.
 

sam_adams

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If you take a look at the Left + Right combined response there is no null at 31 Hz:

Lronly


Looking at the sub response there is a small drop in response at about 33 Hz:

Subonly


When looking at the combined response of the Left and Right with the sub, there is a large drop in the response at about 31.5 Hz:

Lrsub


There is a distinct possibility that the sub polarity is reversed with respect to the Left and Right speakers. If the sub has a polarity switch on it, try setting it to the opposite polarity that it is currently at to see if that fixes the response drop.

The drop in response at 300 Hz may be SBIR. Try placing one of the absorbers that are standing on the floor at the back of the room against the wall behind the speakers to see if that changes the response.

Additionally, you seem to have the sub crossover frequency set very low. Try setting it a bit higher—80 Hz to 100 Hz—to see if you can't smooth out the drop in response at about 57 Hz.
 
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Powermankw

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You can match sub to mains using the Alignment tool in the All SPL graph controls to work out the delay required to get a good phase match between sub and main. There are a few threads on that, this is a currently active one.
Thank you. I had an issue with phase being flipped in my speaker, but it is all fixed now. However, when I look at phase, sub goes up positive, and speakers go down negative... That's what I don't get. I have yet to see them matched anywhere.

I did see some bids on the alignment tool. Looks simple, but as I said, none of my stuff seems to match. But I certainly will review what you posted and see if those have my answer.
 

Powermankw

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If you take a look at the Left + Right combined response there is no null at 31 Hz:

View attachment 57271

Looking at the sub response there is a small drop in response at about 33 Hz:

View attachment 57272

When looking at the combined response of the Left and Right with the sub, there is a large drop in the response at about 31.5 Hz:

View attachment 57273

There is a distinct possibility that the sub polarity is reversed with respect to the Left and Right speakers. If the sub has a polarity switch on it, try setting it to the opposite polarity that it is currently at to see if that fixes the response drop.

The drop in response at 300 Hz may be SBIR. Try placing one of the absorbers that are standing on the floor at the back of the room against the wall behind the speakers to see if that changes the response.

Additionally, you seem to have the sub crossover frequency set very low. Try setting it a bit higher—80 Hz to 100 Hz—to see if you can't smooth out the drop in response at about 57 Hz.
Thank you! I spent a couple hours moving sub everywhere, then changing settings everywhere... That was the best set I got with a crossover using a 6db slope. If I changed crossover frequency, it just seemed to move what ever problem I had at the time. In general, I don't want to overlap speakers because I can't cut them off with crossover. I just want add what is missing.... But I'm down for what ever is best.

So I can change phase and swap polarity on sub. When ever I swap polarity, it wipes out bass, so it is definitely canceling, and correct polarity. Sub also has DSP and I can get it really flat, but with speakers, there is a null somewhere. What I measured was the most narrow...never any DSP.

All the panels are 4" mineral wool. 4pcf. All boxes on walks and ceiling are 12" fluffy. On the side walls is 16". The panels behind the speakers are always there. I considered more to cover window. But there are panels behind speakers for the measurements.
 

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ddude003

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Do these Dynaudio Heritage Specials have reflex ports and are supplied with foam plugs? Have you tried the plugs and what is the affect? The speaker specs say it goes down to 42Hz... I would try to find a cross over match to your sub between 45Hz and 65Hz... Generally speaking, a Room Curve & DSP might smooth things out a bit... A little diffusion may also help...
 

Powermankw

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Do these Dynaudio Heritage Specials have reflex ports and are supplied with foam plugs? Have you tried the plugs and what is the affect? The speaker specs say it goes down to 42Hz... I would try to find a cross over match to your sub between 45Hz and 65Hz... Generally speaking, a Room Curve & DSP might smooth things out a bit... A little diffusion may also help...
Yes, rear ports that are tuned to 40hz if I'm not mistaken. My sub is a SVS Micro3000. I'm not trying for a night club, just trying to fill in bottom octaves. The Micro3000 is fantastic for that. I can almost do without a sub because the speakers are very good... But almost. On some stuff, it's needed. Even turning it up to - 30 shows a big boost... So it doesn't need much to get a nice flat response to 20hz with what... 5-7db.

So putting plugs in just rolls off earlier, and may indeed be the ticket at some point. In my head, I would rather hear speaker woofer than sub, but it may be best... It may be best just from a SBIR/mode standpoint.

From my car audio, if you are boosting bass then you need to move the crossover down in frequency to compensate for boost moving it up... But I am not cutting off my mids with low shelf like I can in my truck.

Now that my treatment is finished, and my chairs are showing up tomorrow, I really need to do more measurements to find best speaker/listening position again... Especially with plugs in. Then try again moving sub and settings all over again to see if I can get a better placement and integration with a finished room.
 

Powermankw

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I spent some time just moving speakers closer to wall. Started at 4ft, went to 2ft at 6in increments. The last one was still at 2ft, but one foot closer together. It certainly seems like SBIR and none in particular was great. I was about to do with plugs but the cohabitants had enough.

I have some pretty big issues from my normal place, which isn't perfect. When I did nearfield, it was best I have measured yet. I tried to see what my closest limit was, and it was pretty flat. 4ft from walls, 3ft apart, and 3ft from LP without sub.
 

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