2 track or 4 track reel to reel deck?

what are the advantages and disadvantages between the two options?

For the same size tape and tape speed, a two track deck offers better signal to noise ratio than a 4 track deck.

If you're recording stereo, the 4 track gets better tape economy. Two of the four tracks record stereo in one tape direction. The tape is then flipped (or reversed, depending on the mechanism) to record stereo on the other two tracks.

If you're recording live music, a suitable 4 track deck will allow you to record a seperate signal on each of the four tracks for later mixdown to stereo or mono. Each track can be recorded independently while listening to the others, to allow building of complex arrangements via overdubs. Of course you can get recorders with many more than 4 tracks for this purpose. 8 track reel to reel is very common, and commercial studios can use 48 tracks or more.

Studios usually use 2 track to capture the stereo mixdown from multitrack recorders, for those still using analog.

What do you want to do with the tape deck?
You can only record 4 tracks as stated above, if the reel to reel is 4 Ch 4 trk...I dont see how you could do that with a consumer 2 ch, 4 trk reel to reel.

I have a vintage reel to reel that plays 2 track and 4 track, and it records in 2 track...the frequency response in 2 track is greater by a wide margin. There is a reason that commercially prerecorded reels are so much more expensive that 2 track.
It's been awhile, but I don't believe that you can play a pre-recorded commercially released reel to reel tape (4 track) on a 2 track machine. You can, however, play a 2 track tape on a 4 track machine.
Hi - Be careful not to confuse "2 or 4 track" with "2 or 4 channel" The "tracks" are gaps (slots) in the recording head that actually provide a magnetic signal to the tape. The "channels" refers to the number of input/output signals the deck can handle. You can have a 4 track/2 channel machine OR a 4 track/4 channel machine - they are quite different.

I'll try to simplify the 2 track/4 track differences:
2 Track- Records in only one direction on the tape. You can't "flip" the tape and record the other side. The recording head "slots" are wider, thus using more of the tape to theoretically increase the amount of information recorded. And, since the "slots" are farther apart, the signal-to-noise ratio should be much better, with virtually no "cross-talk" or bleed through.

4 Track - Records in both directions, using 4 "slots" instead of two.
Recording time is doubled, since you can use both "sides" of the tape. But, since they are closer together, you will experience more cross-talk (one play head "hearing" the material recorded on another close-by head "slot".)

Adding to the confusion is the speed of the recording being made. The best would be a 2 track, 15 inch-per-second recording. The worst would be a 4 track, 3 3/4 IPS recording. Most pre-recorded tapes are 4 track, the good ones at 7 1/2 IPS, and the cheap ones at 3 3/4 IPS. Some pre-recorded 7 1/2 IPS tapes sound downright stunning, while virtually all 3 3/4 IPS tapes are pretty bad.

To sum up, if you plan to record live music at the best quality, a 2 track 15 IPS machine is your best bet. If you plan to play back pre-recorded tapes, a 4 track machine is a must. I would avoid any auto-reverse R2R decks, since they aren't usually very "Hi-Fi."

Fatparrot-You can play back 2 track on a 4 track machine, but track 2 (left channel) isn't properly aligned, so the sound isn't balanced - or very good, for that matter.

If you have any further questions, e-mail me & I'll try to help. I'm not a recording engineer by any means, but I've used virtually every type - and most every brand! - of reel-to-reel deck since about 1968, and will be glad to try to answer any specific questions you may have.

Best of luck,
Egoss, three points:

1) There were actually 2 track machines that used a 30 ips speed (recording studio applications only).

2) I said that you cannot playback a 4 track recording (pre-recorded reel to reel) on a 2 track machine. Since a 2 track machine is not reversible, tracks 2&4 will be audible playing BACKWARDS, unless the 4 track tape was recorded in only ONE direction. Non-reversible unidirectional pre-recorded tapes were recorded at 3 3/4 ips, not a speed at which you want to record music.

3) There should be no alignment problem with a 2 track tape when played back through a 4 track machine. The output will be somewhat lower, though.
Fatparrot -
Yup, I didn't mention 30 IPS, since it's not really a consumer speed.

I never mentioned your 4 track comment since I agree that it's correct. :-)

As for your 2 track comment, I have been taught that there is actually a slight difference in the recording slots in a 2 track head compared to a 4 track head. A 2 track head is not the same as a 4 track with tracks 2 & 4 missing. Track 1 (right channel) is slightly moved inward, and track 2 (left channel) is even more off center compared to track 3 on a 4 track deck. Thus, if you try to play back a 2 track tape on a 4 track deck, track 1 on the tape covers all of slot 1 on the head, even though the slot is not wide enough to recover all of the info from the tape. But slot 2 is not fuly covered by track 3 on the tape, so the volume is quite a bit lower and a great deal of the information is not read by the head. If there's an expert out there that has a better explanation, or if what I've been taught is incorrect, please jump in and educate us all. :-)

Have a great week,