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Posted By: ryck Can Bluetooth operate bi-drectionally? - 10/05/20 05:10 PM
In my den I transfer audio from vinyl to digital using my old 21" iMac because it's the only computer I have that has an audio input. The process involves a cable from the turntable to the iMac, then transferring the result to my 27" iMac by burning a CD and playing it back on the 27" with the Apple external CD drive. I have thought about doing this computer-to-computer transfer via Bluetooth but it seems that would take much more time.

However, since my 27" feeds my amplifier via Bluetooth for regular playbacks, I was wondering if Bluetooth can be made to feed the other direction - from the amplifier to the computer. If so, my turntable to amplifier to computer route could be a single process. The tools are: Teac TH-300 turntable feeding Yamaha R-S2020 amplifier; iMac (Retina 5K, 27-inch, 2017); Apple Bluetooth Software Version: 6.0.14d11.
Posted By: joemikeb Re: Can Bluetooth operate bi-drectionally? - 10/05/20 09:13 PM
Bluetooth is bi-directional. The issue is whether the bluetooth hardware in your Yamaha R-S2020 has a transmitter or only a receiver function. I just looked at the Yamaha R-S2020 Bluetooth user guide and there is no mention of sending a bluetooth signal only receiving. However, given your computer is already paired with the Yamaha this is easy to test. Put a favorite vinyl on the turntable then go to Systems Preferences > Sound > Input and select the paired Yamaha as your INPUT source. If the input level is bouncing in time with your music on the Yamaha, you have a two way connection.

If you do get a connection, be aware Bluetooth bandwidth is relatively low 800 KILObps (compared that to WiFi which is easily in the 300 to 1300 MEGAbps range, so you might lose some of the highs in your music. Low bandwidth is not a problem when sending audio files as the signal is not "real time" and can spread the data over time without fear of loss.
Posted By: artie505 Re: Can Bluetooth operate bi-drectionally? - 10/06/20 12:44 AM
If it's feasible, you can boot your 21" iMac into target disk mode, cable it up to your 27" iMac, transfer the music w drag & drop, and skip the CDs.

More: I wonder if a Griffin iMic would work if you could get your hands on one?
Posted By: ryck Re: Can Bluetooth operate bi-drectionally? - 10/06/20 02:59 PM
Originally Posted by joemikeb
Put a favorite vinyl on the turntable then go to Systems Preferences > Sound > Input and select the paired Yamaha as your INPUT source. If the input level is bouncing in time with your music on the Yamaha, you have a two way connection.
Bingo. We have lift-off. I went a step further and opened my Amadeus Pro and was able to record. Now to see if there is any effect on the high-end response although, with my aging ears, anything above 9KHz might be moot.
Posted By: ryck Re: Can Bluetooth operate bi-drectionally? - 10/06/20 03:03 PM
Originally Posted by artie505
If it's feasible, you can boot your 21" iMac into target disk mode, cable it up to your 27" iMac.....
The inability to run a cable to the 27" is the reason I kept the 21". When the 27" came out, Apple dropped the TRS audio cable input.
Posted By: joemikeb Re: Can Bluetooth operate bi-drectionally? - 10/06/20 04:00 PM
Originally Posted by ryck
Bingo. We have lift-off. I went a step further and opened my Amadeus Pro and was able to record. Now to see if there is any effect on the high-end although, with my aging ears, anything above 9KHz might be moot.

👍 Glad it worked, and I 🦻🏻 what you are saying about the high ♬ ♪ ♩ (apologies for the PUNishing remark.)

By-the-way, you might want to take a look at Rogue Amoeba's SoundSource app. It is great for redirecting and customizing inputs and outputs. Works great in Catalina, but like many apps that use kernel extensions remains a work-in-progress for Big Sur.
Posted By: artie505 Re: Can Bluetooth operate bi-drectionally? - 10/06/20 04:44 PM
Originally Posted by ryck
Originally Posted by artie505
If it's feasible, you can boot your 21" iMac into target disk mode, cable it up to your 27" iMac.....
The inability to run a cable to the 27" is the reason I kept the 21". When the 27" came out, Apple dropped the TRS audio cable input.
You misunderstood me.

My suggestion is to use the 21" iMac's audio input jack to import your music and to then transfer it to the 27" iMac with drag & drop by cabling the two iMacs via firewire.

That would avoid both the CD step and Bluetooth limitations.

Update: But one of the adaptors to which joemike linked is a better option.
Posted By: joemikeb Re: Can Bluetooth operate bi-drectionally? - 10/06/20 04:58 PM
Originally Posted by ryck
The inability to run a cable to the 27" is the reason I kept the 21". When the 27" came out, Apple dropped the TRS audio cable input.

There are any number of adaptors that will convert analog audio to USB digital and vice versa ranging in price from $5 to $30 at Walmart or Amazon. Price depending on features and number of inputs and outputs and could easily replace the 21".
Posted By: artie505 Re: Can Bluetooth operate bi-drectionally? - 10/06/20 05:02 PM
Originally Posted by joemikeb
Originally Posted by ryck
The inability to run a cable to the 27" is the reason I kept the 21". When the 27" came out, Apple dropped the TRS audio cable input.

There are any number of adaptors that will convert analog audio to USB digital and vice versa ranging in price from $5 to $30 at Walmart or Amazon. Price depending on features and number of inputs and outputs and could easily replace the 21".
They appear to be the current incarnation of the old Griffin iMic I mentioned.

If I ever work up the energy to get back to importing vinyl, one of them will be the enabler. smile
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