Bass direction is audible

[sigbergaudio]

I like calibration but I don't want to live and die by the graphs and charts. There are some perceptual advantages with a multi subarray like decrease localization. Having dedicated mid bass components create better transients then asking my larger subs or speakers figure out the mid bass. And I want to clarify I am definitely not against expensive equipment I would love to have four sigberg audio 10Ds ) , I just think that a lot of people are not getting the most of what they already have

Many subs are certainly a good idea, and dedicated capacity for the midbass is also a good idea.

 

[bmc0]

Less than 8% total harmonic distortion and less than 1% high order harmonic distortion at a real world SPL listening level.

The "distortion" just looks like noise to me. Note how the peaks don't really line up with the harmonic frequencies except perhaps the 3rd harmonic (67.35Hz).

I have only two 15 inch sealed subs in my setup (Dayton RSS390HF-4 in DIY enclosures) and I measure approximately 0.3% THD average (1% peak) through the subwoofer range at a similar SPL:

 

[sfogg]

I will have to try measuring distortion on my subs at some point. I know my old Contrabass was rated at 1% distortion at 114db. But that was also a strange beast in that distortion rose at lower levels due to belt/motor noise. My current system has (2) 6' sealed cabinets with 2 Revel Sub1500s in each cabinet. I also have the Contrabass cabinet with 18" passives and (2) Revel Sub1500s in that too. (The contrabass 15" active woofers foam rotted out)

 

[bmc0]

When I listen to music, I always have the correlator in sight in the DAW and I have never seen signal below 100hz with ITD.

Interesting as quite a few of the tracks I've analyzed have significant fluctuations in inter-channel phase below 100Hz. I posted some examples in the "Bass and subwoofers" thread:

• A few X-Y plots here and here.
• Short-time cross-correlation plots.
• Plots showing fluctuation of the short-time cross-correlation over time (a crude attempt at an "LF envelopment" metric).

As already mentioned, recordings of symphony orchestras made with widely-spaced microphones will generally have pretty low correlation below 100Hz.

 

[sfogg]

The purpose of Bass Enhance on Lexicons was to increase ITD to simulate the effect that a large hall has on bass.

 

[andrewtungnguyen]

The "distortion" just looks like noise to me. Note how the peaks don't really line up with the harmonic frequencies except perhaps the 3rd harmonic (67.35Hz).

I have only two 15 inch sealed subs in my setup (Dayton RSS390HF-4 in DIY enclosures) and I measure approximately 0.3% THD average (1% peak) through the subwoofer range at a similar SPL:
View attachment 451718 View attachment 451719

You’re right, the harmonics don’t line up perfectly beyond the 3rd. It was a four-burst test at –5 dB with mains and all four subs playing, so SNR was only around 5 dB. There’s definitely some noise in the measurement. I’ll run it louder at 0.0 dB once I seal the ported sub and get the dogs out, that should clean things up and show a clearer picture.