Need Help w/ Polk Audio Mod

[Narv]

The Jackson Center audio engineers placed the 2015 Classic's four speakers at the extreme ends of the trailer...2 over the sofa and 2 at the head of the beds. I would like to use a small Bluetooth speaker on the dinette table so that I don't have to turn the volume up so loud. Since the Polk Audio PA450UM unit is "Bluetooth capable" I thought this would be a relatively simple matter. From reviewing other threads, I came to find out the unit is only capable of receiving Bluetooth signals...not transmitting. Okay, I need a Bluetooth audio transmitter...still relatively simple; but where does the Bluetooth transmitter pick up its audio signal? The existing speakers are wired from a 16-pin modular connector at the back of the tuner/amp module. The tuner/amp module also has 2 pairs of RCA cables exiting it. One pair is unused and labeled "Rear Left & Right Aux Out" and the other pair labeled "Front Left & Right Aux Out" goes on to a Pyramid NS-20 Noise Suppressor Isolation Transformer and then joins a large wire bundle that disappears into the cabinet cavity between the refrigerator and the dinette wall where the television is mounted. I was hopeful the unused pair of RCA cables would give me an audio signal, but that doesn't appear to be the case. Moreover, if I disconnect the pair of RCA cables joining the large wire bundle, nothing seems to happen (i.e. no effect on sound whether in radio or aux/television mode). I am very electronics-challenged; can someone come to my rescue? I apologize for the long post; thanks for your patience if you've gotten to this point.

[bel73]

Narv

Here is something that might work for ya.

https://clearsounds.com/product/qlinktv-bluetooth-stereo-audio-transmitter#1450062313575-fd6a14b2-d634

If the rear RCA are not being used the above device should work. Your front RCA connectors might be going to a subwoofer.

[HiJoeSilver]

Check the fade setting on the radio. Since the RCAs were only on the front and not the rear they may have adjusted fade to all front so nothing is going to the rear RCAs.
I think the RCA to Bluetooth will be your best bet once we figure out the output from them.

Never mind, if the fade was set that way it would affect the output via the 16 wire harness from the radio. The RCA connector may not go anywhere. Do you have a home speaker you could plug them into to see if they're providing an output. Or check if there's a dc voltage between the rca inner post and outer post when the radio is playing music. I looked at the manual and it seems like the rca should output.

[Narv]

bel73,

I already have a Bluetooth audio transmitter in mind, but I was first trying to test the Polk Audio with wired speakers to make sure that the RCA outputs would work. I had taken two old computer speakers and connected them using a 2-RCA x 3.5mm female adapter. As HiJoeSilver suggested, I just now checked for current at the RCA's and got nothing on the meter.

Good idea on the subwoofer...I had forgotten about that, which is located under the dinette seat. That reminder afforded me the chance to adjust its controls for better overall sound. However, the subwoofer is apparently also driven via the 16-pin connector...if I unplug the Front L/R Aux Out connectors, the subwoofer is still operational.

Unless someone else has any ideas, I guess I'm at the point where I need to query Polk Audio about those RCA Aux Out's; and then maybe further follow up with Jackson Center. It is still most puzzling where the connected Front L/R Aux Out's are going. This is another example of why it would be nice to get complete wiring diagrams from Airstream.

[Narv]

I just re-read another thread of a couple of months ago by beetlebob on this same issue. Jeff4506 had posted and it sounded like he had the unused rear RCA aux out working with a Bluetooth transmitter in exactly the manner I want. In his case, he also said the front RCA aux out was driving the subwoofer; so something is definitely different in our installations. I will contact Jeff4506 directly to see if he had to do anything to get an audio signal from the RCA aux out's.

[dbusse]

Don't forget about the powered subwoofer under the seat that you are probably kneeling on. That's likely what the RCA cables are feeding. You can get a "Y" splitter without degrading the signal, and feed that into your Bluetooth transmitter. You could probably co-locate it under the seat adjacent to the subwoofer.

Dan

[bel73]

Originally Posted by Narv

As HiJoeSilver suggested, I just now checked for current at the RCA's and got nothing on the meter.

Narv

Playing music at a normal listening level the RCAs are going to put out a very low voltage. Would be very difficult to read on an average multi meter. You would really need an oscilloscope and play a test tone or a pulsing DC tone. If you have a long RCA cable try to connect the output of the radio to one of the inputs on the TV and see if you get sound that way (change the TV to whatever source you plug into of course).

Good luck, hope you get it going!

[Narv]

I finally figured out that everything is working correctly and that I do have an audio signal coming from the rear RCA aux outs. Two mistakes on my part:

1. The front RCA aux outs are indeed wired to the subwoofer. Previously I thought I had unplugged the front RCA aux outs to test for that, but amongst the mass of wires I had apparently instead unplugged the RCA aux ins that allow the DVD/TV audio to be heard on the Polk Audio speakers.
2. The very first thing I had tried was hooking up a set of computer speakers to the rear RCA aux outs. I didn't think there was any audio, but it turns out there really was...I just couldn't hear it because of the volume. The speakers I used had no volume knob...only controllable via the computer's operating system. When I put my ear close to the speaker, I could hear the faint signal.

Now all I need to do is buy a Bluetooth audio transmitter and I should be good to go.

THANKS everyone for your help!

[cory_can]

It was identified in the other thread but you may want to pay special attention to the latency of the Bluetooth transmitter that you select so that the speaker outputs are closer to being in sync.

[beetlebob]

I have found out that there is a slight delay in the Bluetooth speaker from the wired ones so you get a echo effect. I had a customer who builds sound studios in to look at it and he told me to replace the 4 ohm speakers out with 8 ohm speakers. Then you can add two more speakers to each channel so then you can have a total of 8 speakers to the system without hurting the amp from the radio. 4 ohm speakers have a better sound that is why they use them. But we are not running a sound studio and the difference in sound quality will not be noticeable since we will now have better sound movement in the trailer from the additional speakers. Once I make it back into civilization and out of the forest I am now working in I am going to just add 2 more in the front and see how it sounds

[Narv]

Just a final update to this thread. I purchased an Aluratek M/N ABT01F Bluetooth audio transmitter, connected it to the unused rear RCA out's and paired it to an EasyAcc Mini Portable Bluetooth speaker. It works beautiful with no delay or echo from the Airstream OEM speakers. Thanks again to everyone for your help.