Racks... The Next Frontier

[GrimSurfer]

Pity - Ikea made the famous table where the Linn LP12 was supposed to sound best.

Do you lack a rack? Maybe you have a rack that's not a lack? If so, take it back. The lack makes a perfect rack!

 

[LTig]

You people sneer superiorly at these reviews but offer nothing to justify your position.

Have there been measurements of the effects of racks, and isolation products generally (as that is what racks claim to be)?

Not that I know of, but with the exception of vinyl players (where a solid foundation is essential - see below) the only possibility to modify sound in electronics by vibration is microphony, which is a well known phenomenon. If you tap a big capacitor in a microphone preamp at full gain with a screwdriver you may hear a thumb noise. This is however a much stronger mechanical impulse than what may occur through vibration. Taking this in account, and reducing the gain by some 60 dB any effect must be inaudible although @amirm's AP may be able to measure it.

For vinyl players I'd like to report my subjective experience with my Linn LP12 (belt drive, subchassis). Placed on a very heavy stone plate the sound of the LP12 was worse than placed on a 19mm thick MDF board with 3 mounted spikes (cheapest ones). A player without subchassis has been said to sound better on a stone plate. My "theory" for an explanation is:

• A player with a subchassis is very good in damping low frequency vibrations but not so good with higher frequencies.
• A player without a subchassis is usually very good in damping high frequency vibrations but not so good with lower frequencies.
• The MDF board damps high frequencies better than low frequencies.
• The Stone plate damps low frequencies better (by its sheer mass) than high frequencies.
• Combining a player with a foundation which damps those frequencies the player has problems with results in better overall damping of all frequencies which improves SQ.

Take all this with a bucket of salt, please. But I'm sure there are several members here with much more knowledge who are able to correct my "theory".

 

[Soniclife]

the only possibility to modify sound in electronics by vibration is microphony

I'm reminded of the following video.

 

[MattHooper]

I can see that rack designed to decouple a turntable from ambient vibration might be useful (assuming the turntable can't do it), but ambient vibration levels in the home are so low and solid state equipment so unaffected by vibration that imagining a rack will affect sound quality is delusional.

I thought it wise to isolate my turntable. My son, about 6 feet tall, 175lbs, literally stomps the ground as he walks. The house shakes like Godzilla is coming when he's moving around. Easily made records skip on my last turntable when walking through that room. I also have a big air conditioning unit on the outside wall near the turntable which can shake the place with low vibrations when operating.

A spring-based isolation platform did the trick.

Aside from that, I don't worry about vibrations for any of my components. (Though I do have tube amps and a tube pre-amp, I honestly don't know how much these could be affected by similar vibrations and haven't bothered to do anything about it).

 

[LTig]

I'm reminded of the following video.

If I do the same with my RME ADI-2 PRO fs, using REW's RTA display, nothing happens at all. With 192 kHz samplerate and 128k FFT size the noise floor stays constant at -130 dB.

However if I connect an unbalanced cable and tap this cable with my fingers the noise floor rises some 20 dB, starting at 200 Hz (and below).

 

[LTig]

I thought it wise to isolate my turntable. My son, about 6 feet tall, 175lbs, literally stomps the ground as he walks. The house shakes like Godzilla is coming when he's moving around. Easily made records skip on my last turntable when walking through that room. I also have a big air conditioning unit on the outside wall near the turntable which can shake the place with low vibrations when operating.

A spring-based isolation platform did the trick.

What kind of turntable is it?

 

[SIY]

Don't forget tube amps. I once witnessed an audition of the big Avantgarde Acoustic Trio with 2 active subwoofers. They were driven by tube amplifiers located in a nice rack. When they played vinyl very loud the whole thing started to resonate at very low frequencies. We blamed it on the microphonic behaviour of the tubes - probably those in the phono preamp - since the distance between the speakers of the sub and the amplifier was less than 1 m. So even the rack did not help.

This can often also be cause by incorrect power supply decoupling, so-called “motorboating.”

 

[Martin Takamine]

While I shop for an audio rack or racks, I setup one made of fabric wrapped cinder block and MDF. I don't want to bend over to play a LPs so the TT is on a base 36" off the floor and weights 250 lbs, vibration is not an issue.

 

[JeffS7444]

For vinyl players I'd like to report my subjective experience with my Linn LP12 (belt drive, subchassis). Placed on a very heavy stone plate the sound of the LP12 was worse than placed on a 19mm thick MDF board with 3 mounted spikes (cheapest ones). A player without subchassis has been said to sound better on a stone plate.

I no longer have an Linn Sondek turntable, but awhile back as I was toying with my Audio Technica LP120, it occurred to me that I could gauge some effects of some turntable tweaks simply by setting the stylus down into a blank groove of a stationary record and checking the output as I tapped the plinth, the platter, the shelf, etc. I didn't figure out how to generate a waterfall plot showing frequency and magnitude vs time, but since I have a real time analyzer display on my Behringer DEQ2496, I just looked at that.

One thing which immediately struck me was how much subsonic crap it was picking up at all times! I did not have any alternative isolation bases or feet to try out.

 

[GrimSurfer]

My stand mounted speakers are sitting on top of a tiled foundation wall, the top of which is angled to support a hearth which was removed and replaced by a flush fireplace. That wall is at least 80 tons, so exciting that much mass is pretty much impossible.

The surrounding wood floor is partially decoupled from that wall by a foam strip, the ones used to insulate wooden top plates from foundations to prevent wicking (I installed this during a reno, mostly to allow expansion and contraction of the oak flooring). It seems to do the trick.

Acoustically inert or high mass materials work as long as the base and rack is stable. TTs and tubes are a little more challenging to fully isolate but I moved away from both 30 years ago so don't have to cross that bridge.

 

[Martin]

May I ask about how much those cost you to put together. I have always liked the 80/20 erector sets and considered building a rack out of it.
I may add some 80/20 struts to my aluminum server rack to add tip over stability. But I may just use some hardwood and put a nice finish on it.

Unfortunately, I no longer have my cost information. (I was actually surprised to find I no longer had it because I keep everything.) From an old brochure I found my asking price for the 3 shelf rack was $1,039.99 and I recall was shooting for a 50% markup so that places the materials at around $693.33. The butcher block was about a quarter of that so you're probably looking at about $520 in 2009 for the 80/20 components. That included machining. Hope that helps.

80/20 regularly sells components on Ebay plus their pricing is on their website: https://8020.net/

Martin

 

[MattHooper]

What kind of turntable is it?

Transrotor Fat Bob S.

Benz Micro Ebony L cartridge

Acoustic Solid 12" arm.

(Sold to me as a package, second-hand).

 

[Wombat]

I needed more rack shelves. For less than $(US)100 I purchased this from Ebay:

Castors can be replaced with spikes. $(US)8.00

Or feet:

What more could one want?

 

[Hipper]

The idea that we don't need any sort of isolation devices, including racks, because equipment should have no flaws is clearly preposterous. Amir has shown that some equipment that is easily available and even popular has its flaws (PSAudio Perfectwave DAC being an obvious example). It seems likely to me that equipment can be less then perfect in many ways, including their construction and feet. If we accept that then it is reasonable to consider ways of dealing with such shortcomings. Racks and isolation devices are one way.

Microphony, seismic vibrations, turntables, spikes and other feet..... It is clear there are areas where isolation devices, including racks, may play a part. For example, using common sense, which seems to be acceptable on here, turntables seem clearly vulnerable to vibrations. Other equipment with moving parts such as CD Transports could also be at risk. It's less clear why a DAC or amp should be troubled by external vibrations unless microphony plays a part.

I don't know the answers but I do know of some attempts to find answers:

https://pinkfishmedia.net/forum/threads/microphony.174095/

Unfortunately it seems the images are lost but the text explains most of it. The general thought was there are effects but they are so tiny as to be irrelevant.

This theory makes sense to me.

http://www.barrydiamentaudio.com/vibration.htm

Townshend explaining his products:

As always, there may be an effect but is it audible in practical use?

In my own very limited experience I detected an effect from adding a lot of isolation devices - feet and shelves - to all the gear and speakers. The effect is described as 'less smeared transients'. It was a small effect, undoubtedly not worth the investment, but it was there. How to measure it I've no idea. It certainly was not expectation bias as I didn't know what to listen for. I just heard a change - the sound was a bit louder and things like rhythm guitar and piano were a bit more noticeable. That turned out to be what less smeared transients sounds like.

I would love a full investigation on this matter. It strikes me there is a lot of confusion and lack of understanding in the area (certainly with me before anyone else says so!)

 

[SIY]

Two seconds tapping on your amp should be all the experimentation you need to convince yourself that dismissing this scam is the opposite of "preposterous," your uncontrolled and sighted "listening" impressions notwithstanding.

It certainly was not expectation bias ...

Riiiiiiight.

 

[BDWoody]

I needed more rack shelves. For less than $(US)100 I purchased this from Ebay:

View attachment 36727



View attachment 36728


Castors can be replaced with spikes. $(US)8.00

View attachment 36729
Or feet:

View attachment 36730

What more could one want? View attachment 36731

Yeah, but how does it sound?

 

[Killingbeans]

Other equipment with moving parts such as CD Transports could also be at risk.

Laser assemblies are usually already mechanically decoupled in several ways.

 

[anmpr1]

Equipment rack for the well heeled audiophile, circa 1976.

 

[gene_stl]

Unfortunately, I no longer have my cost information. (I was actually surprised to find I no longer had it because I keep everything.) From an old brochure I found my asking price for the 3 shelf rack was $1,039.99 and I recall was shooting for a 50% markup so that places the materials at around $693.33. The butcher block was about a quarter of that so you're probably looking at about $520 in 2009 for the 80/20 components. That included machining. Hope that helps.

80/20 regularly sells components on Ebay plus their pricing is on their website: https://8020.net/

Martin

Thank you for that info which is consistent with what the pricing seemed it would be. Even at the materials cost it was a little more than I really wanted to spend. Aluminum server racks can be gotten for almost free. I do intend to maybe doll them up a little if I live long enough.


The Crown stuff above is probably in a Barzilay equipment rack.(or maybe just stackable walnut cases) My Pioneer rack got sold when the guy I gave it to got a big tall Barzilay rack. Beautiful!! He passed away and his brother did too and the Barzilay escaped me. Just barely but it did. You can't win them all.

Regarding turntables I have a recollection of placing the tonearm down on a still record and shouting at it and having the LP act like a microphone diaphragm. I have also experienced motorboating but you pretty much either have be trying to make it happen , OR listening at levels you shouldn't be listening at.

I like Frank Dernie's comments about the reverb added by speakers when digitizing LPs. Makes perfect sense.

 

[LTig]

The idea that we don't need any sort of isolation devices, including racks, because equipment should have no flaws is clearly preposterous. Amir has shown that some equipment that is easily available and even popular has its flaws (PSAudio Perfectwave DAC being an obvious example).

Can't remember that the PSAudio Perfectwave DAC had problems with vibrations.

It seems likely to me that equipment can be less then perfect in many ways, including their construction and feet. If we accept that then it is reasonable to consider ways of dealing with such shortcomings. Racks and isolation devices are one way.

Before we delve into solutions (racks and isolation devices) we should ensure that there are any such shortcomings in the first place.

Microphony, seismic vibrations, turntables, spikes and other feet..... It is clear there are areas where isolation devices, including racks, may play a part. For example, using common sense, which seems to be acceptable on here, turntables seem clearly vulnerable to vibrations.

TTs are certainly vulnerable to vibrations.

Other equipment with moving parts such as CD Transports could also be at risk.

No. Knowing how a CD player works this is almost impossible. Just knock with your fingers on the player while it plays. If there are no interruptions or stutters then vibrations (much lower amplitude than knocking) cannot have a sonic impact.

It's less clear why a DAC or amp should be troubled by external vibrations unless microphony plays a part.

I don't know the answers but I do know of some attempts to find answers:

https://pinkfishmedia.net/forum/threads/microphony.174095/

Unfortunately it seems the images are lost but the text explains most of it. The general thought was there are effects but they are so tiny as to be irrelevant.

This theory makes sense to me.

http://www.barrydiamentaudio.com/vibration.htm

Uh huh ...

[..]In my own very limited experience I detected an effect from adding a lot of isolation devices - feet and shelves - to all the gear and speakers. The effect is described as 'less smeared transients'. It was a small effect, undoubtedly not worth the investment, but it was there. How to measure it I've no idea. It certainly was not expectation bias as I didn't know what to listen for.

I fear you are sadly mistaken here. There is always bias - knowingly or not - if listening is not controlled (DBT).

I just heard a change - the sound was a bit louder and things like rhythm guitar and piano were a bit more noticeable. That turned out to be what less smeared transients sounds like.

I would love a full investigation on this matter. It strikes me there is a lot of confusion and lack of understanding in the area (certainly with me before anyone else says so!)

If it is louder than it can easily be measured even with the cheapest soundcard. Post results please.