Subwoofer Situation

[luft262]

Looks like you've done a good job eliminating room issues, but I wonder about your sub response. It is rising towards 100 Hz instead of falling. Is that intentional? It doesn't look like a normal bass response I've seen in a room and it doesn't blend well with your speakers.

Ideally your sub would be 5-10 dB higher at 20 Hz vs 100 Hz or so.

Ok. I'll shoot for that.

 

[Chromatischism]

For example, this sounds exceptionally powerful yet balanced:

 

[luft262]

For example, this sounds exceptionally powerful yet balanced:

View attachment 184701

How's this?

 

[Sancus]

If reference is theoretically 85dB and we want the sub to have a dynamic range up to 115dB that means we need the subs to get up about 30dB above the listening level during spikes. If a normal person is usually watching movies at closer to 65 to 75dB, which is still pretty loud, they would want their subs to get up to 95 to 105dB. Is that correct?

Hard to make heads or tails of this post. "thx reference" as commonly cited/calibrated by Denons means that -20dBFS pink noise will produce 85dB from 1 speaker. There is no spec for multiple speakers playing the same signal, and that will produce different results in different rooms.

For the LFE, -20dbFS should produce 95dB, and therefore in both of these cases you should get 105dB and 115dB respectively with a 0dBFS signal. Note that to actually trigger the LFE +10dB boost you need to send a signal via the LFE. Not via individual speaker channels. You probably aren't using the LFE channel for sweeps.

As for the measurements, all I see are subs being asked to produce >115dB and heavily compressing in the lower octaves because they can't do that. That's normal. You need very extreme subwoofer power to actually produce 115dB at 20hz in most rooms. We're talking multiple 18" subs, or even more. It looks to me like your subs can manage 103dB or so, which is close enough for -10dB listening if you are using a flat target curve. If your Audyssey target curve has 5dB of boost(or you raised the sub volume), then it's enough for -15dB, and so on. This is assuming you want the curve to be maintained at all levels. Most people's systems probably DO heavily compress below 40hz, and they are used to it. It is rare to see people with sufficient sub power to play "thx reference" level at home.

Content is not standardized, so all these volume levels only apply when using test signals. I tend to listen around -10 at home, +/- 5dB for content variance, but everyone and every content source is different.

 

[Chromatischism]

How's this?

View attachment 184737

View attachment 184738

I bet it sounds a lot better! That is just a change to the sub, right?

 

[Chromatischism]

You need very extreme subwoofer power to actually produce 115dB at 20hz in most rooms. We're talking multiple 18" subs, or even more.

Agree with everything, except this – it depends if we're talking sine sweep or burst. On a sine sweep yes, but I can hit 125 db at 30 Hz on a burst with 2 vented 15" subs in a small room. I haven't tested to see what they can do max at 20 Hz. Kind of afraid, haha.

 

[Sancus]

Agree with everything, except this – it depends if we're talking sine sweep or burst. On a sine sweep yes, but I can hit 125 db at 30 Hz on a burst with 2 vented 15" subs in a small room. I haven't tested to see what they can do max at 20 Hz. Kind of afraid, haha.

Yeah, but spec is very clear that continuous output at 105dB(individual channels) and 115dB(LFE) is the requirement, so bursts don't meet the spec at all. When you consider the impact of bass management on the LFE in particular, requirements in some film content are likely to approach 115dB for seconds(or even exceed for non-Atmos content that isn't limited) if you are actually playing at 0dB. Not that I would recommend anyone play at 0dB at home. Even Dolby thinks that's too loud, they recommend 79-82(-6 to -3).

 

[luft262]

I bet it sounds a lot better! That is just a change to the sub, right?

Yes. I added a -12 dB house curve at 100Hz in the Audessey app and changed the PEQs on my subs a bit.

 

[luft262]

I bet it sounds a lot better! That is just a change to the sub, right?

And yes it sounds better!

 

[AE1]

What if I do that and I still don't get the punch I wanted?

Can I ask how did you fixed this issue. And could you not just put the old subs back in and measure what you were getting room response wise and then swap the svs back in to see what the difference was. I ask theses questions as I have a similar issue sort of and its hard for a novice to pick through the measurements. I have swapped a much more capable sub for another with meah results.

 

[Willem]

And yes it sounds better!

I am glad you managed to get the integration with the main speakers more or less alright. I am in a somwhat similar situation with just two subs (once one of them is back from repairs) in a large (some 7000 cubic feet) open plan listening space. So I thought about what you could do next, with or without spending some serious money. These would be my steps:
1 get Multi Sub Optimizer, for better subwoofer equalization than your AV receiver can do. You can use the filter suggestions as input for your SVS subs. This will cost you nothing other than time.
2 The same, but now add a minidsp 2x4 HD to allow more, and more sophisticated, filters. You wrote that you do not want to use the 2x4HD because it did not measure very well, but if you only use it for the subwoofers this will not be audible. This will still be a cheap upgrade with probably quite audible improvements.
3 Add your two cheap existing subwoofers if you still have them. They will not add low end extension, but they may smoothen the response a bit, and over a wider listening area. See here for inspiration: http://archimago.blogspot.com/2020/05/musings-measurements-subwoofers-to.html
4 Either, and here it gets expensive, expand on this idea with two additional SB3000 subwoofers. This will give you quite a bit of additional power, and a smoother response over a rather wider listening arrea.
5 Or use a similar amount of money for just a third but this time really big subwoofer, preferably located in a corner for additional reinforcement. This is the one advocated by Earl Geddes. It will give you a lot of really low output, and a somewhat smoother response over a wider listening area, though not as smooth and wide as with a total of four subs.

 

[Chromatischism]

If you use MSO, you need the MiniDSP.