Projector picking up AM/FM station in the background

[jussig]

Hi there,

My name is Jussi, I am very new to the amazing world of "audio" and this is my second post. I apologize in advance if i sound like i don't know what I am talking about because I probably have no idea what i am talking about. I really appreciate any advice I can get.

We recently moved and once i setup our "home theatre" system i noticed am/fm station in the background. I have an optima projector connected to macbook pro via hdmi. The audio is connected via AUX from the macbook pro to Marantz 2325 with Klipsch RF7 speakers. Any recommendations how to get rid of it please it is driving me crazy. Thank you.

 

[Eppie]

That's an old receiver. How long is the run from the Macbook to the 2325? Those 1/8" to RCA cables are usually pretty cheap and only good for short runs. I suspect that cable is acting like an antenna. You could try a better quality cable but the Aux audio out on most laptops is not that high a quality signal. Another option is to use a USB cable instead for digital audio, which will not be susceptible to radio interference. Then connect the USB cable to a USB Digital to Analogue Converter (they can be found on Amazon) and use a short RCA cable to connect the DAC to the 2325. Make sure the USB cable has the correct ends as many DACs use USB Type B. Also make sure the DAC has a USB input as many DACs on Amazon have optical (SPDIF) inputs for connecting to TVs and you don't want one of those. Something like a Topping D10s.

 

[TLS Guy]

Hi there,

My name is Jussi, I am very new to the amazing world of "audio" and this is my second post. I apologize in advance if i sound like i don't know what I am talking about because I probably have no idea what i am talking about. I really appreciate any advice I can get.

We recently moved and once i setup our "home theatre" system i noticed am/fm station in the background. I have an optima projector connected to macbook pro via hdmi. The audio is connected via AUX from the macbook pro to Marantz 2325 with Klipsch RF7 speakers. Any recommendations how to get rid of it please it is driving me crazy. Thank you.

Does this happen on all inputs? We need to know which ones.

Funnily enough, with this problem the culprit is usually the speaker leads. This happens as speaker leads pick up RF signals and feed the signal back to the high gain stages via the negative feedback loop. We have had a number of instances of this here over the years.

So disconnect each input one by one. Then see if you have the problem. If you do, then the problem is likely from the speaker leads picking up a local radio station.

The solution is RF blockers in the speaker leads at the receiver end. The problem is, you have to design and build that RF blockers specifically for the frequency of the offending radio station.

These are blockers I made last time we had a member with this problem.

 

[jussig]

That's an old receiver. How long is the run from the Macbook to the 2325? Those 1/8" to RCA cables are usually pretty cheap and only good for short runs. I suspect that cable is acting like an antenna. You could try a better quality cable but the Aux audio out on most laptops is not that high a quality signal. Another option is to use a USB cable instead for digital audio, which will not be susceptible to radio interference. Then connect the USB cable to a USB Digital to Analogue Converter (they can be found on Amazon) and use a short RCA cable to connect the DAC to the 2325. Make sure the USB cable has the correct ends as many DACs use USB Type B. Also make sure the DAC has a USB input as many DACs on Amazon have optical (SPDIF) inputs for connecting to TVs and you don't want one of those. Something like a Topping D10s.

I love the way 2325 looks and sounds that's why I am sticking to "old" What would you recommend to play spotify, apple music etc. for the best quality output? I am using headphones jack on ipad, macbook via UAX atm. Is there a better way?

BTW i tried different/newer macbook today and the background noise was gone.

 

[jussig]

Does this happen on all inputs? We need to know which ones.

Funnily enough, with this problem the culprit is usually the speaker leads. This happens as speaker leads pick up RF signals and feed the signal back to the high gain stages via the negative feedback loop. We have had a number of instances of this here over the years.

So disconnect each input one by one. Then see if you have the problem. If you do, then the problem is likely from the speaker leads picking up a local radio station.

The solution is RF blockers in the speaker leads at the receiver end. The problem is, you have to design and build that RF blockers specifically for the frequency of the offending radio station.

These are blockers I made last time we had a member with this problem.

thank you for your reply (your setup looks incredible btw) the backgorund noise was only there when playing video via projector and using the sound system for sound (via aux) When i was playing spotify via AUX or turntable via Phono it wasnt there.

I tried a different/newer macbook laptop today and the background noise was gone. I guess it was the older technology of the previous one.

 

[TLS Guy]

thank you for your reply (your setup looks incredible btw) the backgorund noise was only there when playing video via projector and using the sound system for sound (via aux) When i was playing spotify via AUX or turntable via Phono it wasnt there.

I tried a different/newer macbook laptop today and the background noise was gone. I guess it was the older technology of the previous one.

Well, that solves that then. It was the analog circuit of the MacBook. These types of faults are best solved by a process of elimination.

Headphone jacks from those devices are about the poorest sound quality.

Your problem is that old 1974 receiver. That is OK for analog sources. If you must use it, then it is OK for turntables etc, but if you are going to use digital sources, you need gear from the digital age. To use that receiver you need a competent DAC to do the digital to analog conversion.
Honestly you would be further ahead with a unit from the digital age that already contains a good and competent DAC.

 

[jussig]

Well, that solves that then. It was the analog circuit of the MacBook. These types of faults are best solved by a process of elimination.

Headphone jacks from those devices are about the poorest sound quality.

Your problem is that old 1974 receiver. That is OK for analog sources. If you must use it, then it is OK for turntables etc, but if you are going to use digital sources, you need gear from the digital age. To use that receiver you need a competent DAC to do the digital to analog conversion.
Honestly you would be further ahead with a unit from the digital age that already contains a good and competent DAC.

i wouldn't mind adding a recent one into the mix ... anything from Marantz that you would recommend ? I would like to listen to "digital files" and watch documentaries on my projector with it. Something that would work nicely with the klipsch RF-7 speakers

 

[lovinthehd]

Back in the 70s I had a 2270 and bleed from the tuner into other inputs was the reason I got rid of it eventually....

 

[endylo]

i wouldn't mind adding a recent one into the mix ... anything from Marantz that you would recommend ? I would like to listen to "digital files" and watch documentaries on my projector with it. Something that would work nicely with the klipsch RF-7 speakers
yarovoe.org

you need a competent DAC for digital-to-analog conversion. you can buy a separate DAC or use an AV receiver with a built-in DAC. I would recommend the Marantz HD-DAC1. It is a high-end DAC that provides excellent sound quality. It also has a wide range of inputs including USB, S/PDIF, and TOSlink.

 

[Eppie]

i wouldn't mind adding a recent one into the mix ... anything from Marantz that you would recommend ? I would like to listen to "digital files" and watch documentaries on my projector with it. Something that would work nicely with the klipsch RF-7 speakers

You have a lot of options available. If you are content with using the Macbook as a source, then adding a good DAC like the Topping I mentioned, or an SMSL, would get you better audio with your current Marantz. If you only plan to use the Macbook and two speakers that could suffice for now.

If you plan to add more sources like a WiiM Pro streamer for music or NVidia Shield for video, then upgrading to a new receiver would help. There are two channel receivers with HDMI inputs but the options are limited. Most audio video receivers (AVRs) are designed for multi-channel audio and will have at least 5 channels of amplification or more. You then need to consider how loud you like the audio and how efficient your speakers are to help judge how much power the AVR needs. The RF7 has a pretty high sensitivity though (high efficiency) so you should not need a lot of power to drive those to high volume. It then becomes a matter of budget, features and taste in styling.

 

[BMXTRIX]

I would use almost any modern AV surround receiver. Even if you don't have surround sound, the integrated amplification and HDMI connectivity with built in DACs will clean up the sound of the system tremendously. I've looked on my local Craigslist at times and have picked up some very good deals.

 

[Tulonarinchu]

No worries, we all start somewhere! That background noise might be interference. Try checking your AUX cable connections, make sure they're secure. Also, keep the cables away from any power sources to minimize interference. If it persists, consider using a ground loop isolator or a different audio connection method. Good luck!