Sound Quality from RTL-SDR

[K9DAK]

I just configured this inexpensive SDR:

RTL-SDR Blog V3 R820T2 RTL2832U 1PPM TCXO HF Bias Tee SMA Software Defined Radio with Dipole Antenna Kit.

I'm using the latest version of SDR Sharp with Windows 10.

Interesting, I had the opposite experience... same SDR kit, SDR#... fired it up the first time, tuned in my favorite Chicago FM station and with just a little tweaking of gain and bandwidth it sounded just fine on my ASUS laptop.

However, my problem came when I tuned in my town's analog FD NFM VHF frequency... the audio was awful, no matter the bandwidth / gain setting. That was back in August... I put the whole thing away for a while... I have two weeks off at Christmas / New Years, and dedicated a couple days during that time to get things working with SDRTrunk P2 on our StarCom system.

 

[wowologist]

Actually with a say..o 20 second (A.V) recording of your screen with your phone and uploaded we all may have a better insight, a lot of good reply's but were all still blind without hearing the actual audio and seeing what your waterfall etc is doing and your hearing as a starting point.

 

[DRL-XM43]

K9DAC Me too... it is very good on my end also, same set up.

 

[dragon48]

I ran into this too.

The fix is an easy one, but you'd never know it because SDR# is really hard to use with zero in-app documentation.

On the left, open up the Audio Processor plugin and disable "Bandpass filter". It's enabled by default. Fixed.

YOU ARE THE MAN! Problem fixed! Many thanks.

The original sound was like 8 bit audio from a 1980s video game. Now it's back to normal. I can't complain about free software. These kind of issues are usually supported by forums like this. I'm also reasonably sure that I'm getting true stereo separation. I need to spend some time comparing songs on streaming services to be sure. Edit - now 100% sure I'm getting full stereo separation. The intro to "Magic Carpet Ride," by Steppenwolf has some thick left speaker guitar distortion which was reproduced perfectly while listening to Broadcast FM with SDR Sharp.

With broadcast FM, increasing the gain does nothing, but I no longer need improvement.

While playing around, I found the "enable mpx output," setting. It is a little odd. With the defaults, it appeared to just increase the volume, but I played around and was able to produce echos, as if two identical signals were coming out at once, but not at the exact same time. I'm leaving this disabled.

On to some more fun, and more complicated stuff!

 

[spongella]

If you are listening to FM broadcast make sure you set the RTL-SDR to WFM under the Radio option mode selection. If it still sounds distorted then widen the window by using the cursor and mouse to increase the bandwidth of the signal. FM signals are 200 kHz wide so go no further than that. Yes there is a stereo option but never tried that.

As for the gain, adjust it to a higher setting for weak stations, lower setting for strong. Your RF gain setting all depends on your antenna and the distance you are from the broadcast station. Everyone's situation is different.

Go to the RTL-SDR.com website for excellent ideas on how to use you RTL-SDR. There is a learning curve with this approach.

As for software I use SDR# which is excellent and on occasion, HDSDR. There are other programs out there with more complicated dashboards but my recommendation is SDR# for now, get your feet wet, then if you crave more bells and whistles charge on,

 

[DRL-XM43]

If you are listening to FM broadcast make sure you set the RTL-SDR to WFM under the Radio option mode selection. If it still sounds distorted then widen the window by using the cursor and mouse to increase the bandwidth of the signal. FM signals are 200 kHz wide so go no further than that. Yes there is a stereo option but never tried that.

As for the gain, adjust it to a higher setting for weak stations, lower setting for strong. Your RF gain setting all depends on your antenna and the distance you are from the broadcast station. Everyone's situation is different.

Go to the RTL-SDR.com website for excellent ideas on how to use you RTL-SDR. There is a learning curve with this approach.

As for software I use SDR# which is excellent and on occasion, HDSDR. There are other programs out there with more complicated dashboards but my recommendation is SDR# for now, get your feet wet, then if you crave more bells and whistles charge on,

SDRSHARP USERS GUIDE

SDRSharp Users Guide

This is an excerpt from our book on RTL-SDR which we've decided to post given that many new users struggle to understand all the settings in SDR#. SDR# is currently the most popular SDR program used with the RTL-SDR. It's easy to set up and use. To install SDR#, go through our Quickstart Guide...

www.rtl-sdr.com

 

[a417]

FM signals are 200 kHz wide so go no further than that. Yes there is a stereo option but never tried that.

Unless it's a HD radio station in hybrid mode, then it's nearly twice that....but if you're looking for just the FM data and want nothing to do with the digital audio sub-bands...you're fine.

 

[air-scan]

If you have a pure Android tablet with OTG adapter walk around your residence see if the signal clears up any. signal refraction can cause distortion to. SDRTouch or RF Analyzer is good for RTLSDR.

 

[causeway74]

I ran into this too.

The fix is an easy one, but you'd never know it because SDR# is really hard to use with zero in-app documentation.

On the left, open up the Audio Processor plugin and disable "Bandpass filter". It's enabled by default. Fixed.

Good spot. Just noticed that in my own environment. The plugin generates a filters.xml file which seems to be generated via hard coded filter values in the plugin code. I use a custom script to setup my plugins so I'll just update it to copy it my modified filters.xml file instead of allowing plugin to create it automatically.

 

[DRL-XM43]

Did the OP say if he was experiencing the same problem with other bands on the spectrum? Upon reading this, I fired up my SDR, as I am running all of the same software and hardware that the OP is, and my FM commercial stations are loud and clear. I run my PC audio thru a set of studio Mackies, and the FM sounds great thru SDR#.

Same here full stereo and all....

However I have only a few plugin's the ones I actually use. At one point I installed the community plugin thing which for me was a disaster (unfair comment I know, I should have messed with it longer but..... gone!

Back to un-skinned version and my pet plugins

The advantage of SDR# is it is highly configurable, the disadvantage is it is highly configurable. Any issue I encountered was on me.

 

[stealth210]

YOU ARE THE MAN! Problem fixed! Many thanks.

The original sound was like 8 bit audio from a 1980s video game. Now it's back to normal. I can't complain about free software. These kind of issues are usually supported by forums like this. I'm also reasonably sure that I'm getting true stereo separation. I need to spend some time comparing songs on streaming services to be sure. Edit - now 100% sure I'm getting full stereo separation. The intro to "Magic Carpet Ride," by Steppenwolf has some thick left speaker guitar distortion which was reproduced perfectly while listening to Broadcast FM with SDR Sharp.

With broadcast FM, increasing the gain does nothing, but I no longer need improvement.

While playing around, I found the "enable mpx output," setting. It is a little odd. With the defaults, it appeared to just increase the volume, but I played around and was able to produce echos, as if two identical signals were coming out at once, but not at the exact same time. I'm leaving this disabled.

On to some more fun, and more complicated stuff!

Hi, first post and after much searching I landed on this forum for the fix! I had the same issue and this resolved it after disabling the band-pass filter. Like OP, I'm not into SDR for listening to commercial radio, but I knew it did not sound right when I tuned into those freqs.

Thanks again peepoop!!

 

[dragon48]

Welcome to the forum!

 

[numbat]

On the left, open up the Audio Processor plugin and disable "Bandpass filter". It's enabled by default. Fixed.

I created a forum account specifically to click like on this response. Thanks!