Why Would a Turntable Need More than 1 Arm ?

Sunday afternoon, just browsing the $5k and up turntables...why would a TT need more than 1 arm ? To try different cartridges ?

Do you think I could hear the diff between a $10k TT and my PF1000, same cart and stylus ?
Ask Raul, he has more arms than a giant squid. Seriously, some like the convenience of having more then one cartridge always available; big mono collection, just like to have different presentations of the music, whatever. My two phono stages can be connected to two turntables[or arms] at once so I can demo more than one table without long hook up period. I once used two arms but ended up using one all the time; but if you like playing with cartridges multiple arms is a great way to go. Yes, you could hear the differences. ALL turntables sound different and the more expensive ones are almost always better. Worth it? Your call.
I would love to have a universal turntable with three arms - one for stereo LPs, one for mono LPs and one for 78s. Unfortunately, that would require too many compromises. But a two arm deck is fairly easy to do.

Is that showing off?
Why would a turntable need more than one arm? A turntable is an inanimate object that has no emotions whatever. It does not "need" anything. The owner of said turntable may have any one or two of several reasons for wanting to mount more than one tonearm. These are not hard to imagine.
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In addition to stereo/mono reason, one might want different arms/cartridges for different music or/and different experience. How about two turntables with two/three arms each?
Is the use of a Mono/Stereo switch on a preamp/phono stage as effective an alternative to an arm (be it the first or a second arm) mounted with a mono cart/stylus. Is there any trade-off to doing it this way? Is the result the same? Thanks, bird
Many of my customers have more than 1 cartridge.

A single table with dual arms saves space and offers a degree of flexibility not found in a single arm configuration for the hobbyist who wants to experiment with different tonearm/cartridge combinations.

Dealer disclaimer.
or why a phono stage has more than one input or why a preamp needs so many inputs? "Elementary" Watson said.
Birdliver: a mono cartridge will give better results than summing the 2 channels of a stereo one but the switch is worth using if you have one. The mono is doing the job it was intended to do while the stereo cartridge will have movement in a plane that does not exist on mono records, it will work but not as well. Also added complexity is always best avoided, i.e. single channel to stereo signal back to mono.
I agree with Audiofeil and Mesael but my primary reason is
the circumstance that I prefer some kind of music with one
cart and the other kind with the second cart. BTW it is relativly easy to add a second arm to nearly any TT.

- One for Stereo Cartridge, the other one for Mono
- one for this color, the other one for that color of cartridge
- one for Cartridge without, the other one for cartridge with body
- first one was not expensive enough, the other one is
- one 9" Arm and a 12" Arm
or the second one, because you don't trust the set up from the other one
or ... :-)
Yeah, Syntax is right. I have Rhea for my 2 arms TT. Then I have it upgraded to Signature. I was able to borrow Tron but with only one input. Somehow I don't feel complete. When you're already there, it's hard to go back again.
You may have only one arm, for instance with an EMT table, an EMT 997 or Ortofon RMG 309 you can switch easily from Stereo to Mono carts without alignments at all. If you are going to be happy with one tonearm in this constellation you have my respect.

However as stated above there are so many more options if you decide to go for more tonearms and many different carts. It is on the other hand the entry into the ongoing discussion what makes sense? Believe me it makes sense if you start becoming addicted...
I have a Graham B44 arm with 2 wands. 1 for stereo & 1 for mono. My mono records sound much better with my mono cartridge than my preamp in mono mode with my stereo cartridge. I am also thinking of a 3rd wand for a more analytical cartridge.
Why would a turntable need more than one record? "Need" doesn't really enter into this hobby. Mounted on one table, I have a 12-inch arm with an SPU and a variety of headshells, and a 9-inch arm with two arm wands that I switch between a variety of carts, MM and MC. All offer very different sounds, and all sound good to great. I have a friend who has four turntables, all connected and ready to play through the same system. As Lear says, oh reason not the need. Variety is nice. Many roads to Dublin.
As there isn't a single best arm/cart combination. I'm fortunate enough to have two arms on my Platine Verdier - a Schroeder Model 2 plus Allaerts MC1B and a vintage late 70s Hadcock 228 plus rebuilt Decca FFSS MkIV C4E.

When I play a record, I play the first minute or so with each arm/cart. One of them will sound better with that record and it's not always the same combo that comes out tops. Then I listen to the LP with the arm/cart that suits that LP (and the way it's mastered) best.