Recording a bass cab on it's back

[prater]

I saw a video about ten years ago on YouTube when I was first getting started where the engineer was discussing microphone techniques. He stated that he always laid bass cabs on their backs to record. The reason being that the speakers move much more symmetrically and quickly with gravity working with them rather than against them.

I have nothing to base this off of other than that video which I can no longer find. However I have always done this since. I place my cabinet or cabinets on a wooden base, in my case an upside down ego riser so the cable is not squished or the input jack bent. I remove the grill cloth and mic it up. I like the angle because I can better determine distances from the cone itself. It also eliminates floor coupling altogether and room size becomes a non issue as ceiling height is the only factor and my ceilings are acoustically treated.

I can't really determine any audible difference but I like the technique just because it makes placing a mic a bit easier for me visually.

Has anyone tried this, any pros or cons to note?

 

[Stumbo]

I saw a video about ten years ago on YouTube when I was first getting started where the engineer was discussing microphone techniques. He stated that he always laid bass cabs on their backs to record. The reason being that the speakers move much more symmetrically and quickly with gravity working with them rather than against them.

I have nothing to base this off of other than that video which I can no longer find. However I have always done this since. I place my cabinet or cabinets on a wooden base, in my case an upside down ego riser so the cable is not squished or the input jack bent. I remove the grill cloth and mic it up. I like the angle because I can better determine distances from the cone itself. It also eliminates floor coupling altogether and room size becomes a non issue as ceiling height is the only factor and my ceilings are acoustically treated.

I can't really determine any audible difference but I like the technique just because it makes placing a mic a bit easier for me visually.

Has anyone tried this, any pros or cons to note?

Gravity is a bitch. Good to have it on your side!

 

[RobTheRiot]

Interesting.
Never seen or heard of that.

I’m sure it’s not a huge effect, but if you get even a subtle change or difference in sound, it could be worth trying and just another possible tool in the toolbox.

I would question the difference any single facet could cause, but possibly through a combination of all the differences - speaker facing the ceiling, cab not coupled to floor, the gravity/cone thing, etc - maybe you can get a subtle improvement / difference.

Or, even if no sonic difference, (I missed you saying that when I first read the post) you already found a benefit in easier mic placement.

Thanks for sharing; always love to hear the little tricks different engineers use.
I’ve tried a bunch - some are great, some not so much, but always worth the couple of minutes to find out for yourself.

 

[Stumbo]

@agedhorse or @DukeLeJeune might have a comment about this.

 

[RattleSnack]

I did the same with my combo for live gig number of times. Small stage, 2x vox, 4 instruments + miced drums, and very loud FOH too close to us. Laying combo almost flat on the back aiming toward my ears, and just using highs and high mids to hear myself over slamming FOH, and not interfere with others monitors.
But I never saw this in a studio.

 

[agedhorse]

@agedhorse or @DukeLeJeune might have a comment about this.

Placing a speaker on its back adds in the small effect of gravity (ie. the effect of gravity adds to the forward motion of the cone and subtracts from the backwards motion of the cone).

Placing a speaker doesn't decouple it from the floor, it just changes the position of the boundary (not its effect). It also introduces the additional effect of a flat ceiling (primarily on mid frequencies) as it may create a standing wave (similar to pointing the cabinet normal to a flat wall).

This technique may or may not affect the tone, if it does I would expect the difference to be fairly small.

 

[DukeLeJeune]

I saw a video about ten years ago on YouTube when I was first getting started where the engineer was discussing microphone techniques. He stated that he always laid bass cabs on their backs to record. The reason being that the speakers move much more symmetrically and quickly with gravity working with them rather than against them.

I disagree with his reasoning.

On its back, the cone will be moving up and down. So, with gravity on the downstroke, but against gravity on the upstroke. If anything, this is less linear than the normal orientiation. In practice, I don't think the difference gravity makes really matters. It is a much weaker force than the electromagnetic interaction between the voice coil and the magnet.

In my opinion the biggest difference would be the fairly coherent reflection off the floor and back up to the microphone. Suppose the microphone is one foot above the top of the cab, and the cab is 18" wide and one foot deep. The reflection path length would be a little less than three feet longer than the direct path. At about 200 Hz, the floor bounce reflection will arrive 1/2 wavelength behind the direct sound, and will cause a cancellation dip. At 400 Hz, that reflection will arrive 1 wavelength behind the direct sound, which puts it back in-phase, and we'll have a bump in the response. As we go up in frequency the woofer(s) become progressively more directional so this reflection becomes correspondingly weaker.

This reflection is not totally coherent because the reflection path length changes as we go around the box, but ime it is close enough to being coherent to have an audibly significant effect. I have designed home audio speakers that are very short and have the drivers on top firing straight up, similar to a bass cab on its back.

We still get a floor bounce with the cab upright and the microphone in front of the woofer, but the cone's height in the vertical plane spreads out the arrival time of the floor bounce enough so that it become incoherent, especially relative to the much smaller path length difference. Therefore the floor bounce from the microphone being placed a short distance from the front of an upright cab is probably benign.

What the microphone picks up might sound better with the cab on its back, but imo not for the reason stated in the YouTube video.

@Stumbo , thanks for the heads-up. I don't normally venture over here.

 

[Bob_Ross]

In my opinion the biggest difference would be the fairly coherent reflection off the floor and back up to the microphone.

^^This. Since most cabs are taller than they are deep (front-to-back) laying it on the floor on its back just gets the driver deeper into the Invalid Link Removed (and/or gets more of the drivers deeper into the half-space).