sundance-communications.com/forum Forums TDM Business Telephone Systems Samsung Telephones & Systems MOH Quality for Cell Phones (OS7400)

I know this has been posted a couple of times, but I didn't see a definitive answer. I have 2 MOH's and a paging system on one MISC port on a 7400. I built a surface mount box with 4 keystone jacks, one that is a cat5 input from the MISC, one cat5 output for my paging system, and 2 3.5mm audio keystone jacks for the 2 MOH's. I have the two 3.5mm hooked to computers running VLC (shuffle/repeat). It is all wired correctly, paging works, and BGM/MOH works. When someone calls in on a land line MOH is perfectly clear, its breaking up real badly when someone calls in on a cell phone.

I saw one post where the poster has used a high pass filter and remove all bass lower than 200Hz, because the phone was detecting that was background noise. I tried that and it still breaks up, maybe 200Hz is not high enough. As expected it only happens because of cellular codecs filtering anything that is not voice, but because more and more of our callers are cellular I am wondering if there is anything I can do to increase MOH quality for them.

Thank you in advance

I'm not sure how or why it works but we just had one where we switched the output of the MOH box to 8ohm and it works perfect. Before we did that you couldn't even understand what was playing when calling on a cell phone.

I will have to see if I can set that on the driver in the PC. I saw a suggestion someone had of using a transformer to get to 8ohm. Seeing that twice has me hopeful.

What kind of MOH box was it? I dont think my software driver on the PC has that option, but maybe I can either push it through a transformer, or an external audio driver.

On Hold Plus 8000

I will add that to my wish list. Nice little unit, not terribly expensive. I like that it has an impedance switch on the front.

I was able to overdrive the signal from the sound card, and now it sounds just passable on cell, and a touch too loud on a land line. Tradeoffs.

Thanks for the suggestion.

I think that everyone is missing the boat here. This has nothing to do with your connections. It has to do with cell phones in general. They all use VoIP as the transmission protocol nowadays. IP doesn't carry sustained signals, such as music well at all. It only handles voice on an acceptable level since voice is choppy. Digital sampling at a rate of say 64 times per second will cause music to sound terrible.

Your problem can't be fixed and it's going to get worse as IP is coming more and more into play for even land lines.

I was working with a sound engineer yesterday for another customers MOH and he offered up some tips to try that his company uses. He used different software but he said to use the free Open Source Audacity

Open the music in Audacity
Press CRTL-A to select all then go to effects and select High Pass Filter and enter in 450 and hit OK
Then select the low pass filter and enter in 3450 and hit OK
Then select effects, normalize leave the default settings and hit OK.
Now change the project rate to 8000hz (bottom left) and go to file, export and select WAV Microsoft signed 16 bit.

I tried it on a couple of sound files that didn't work here at our office and had pretty good success after the conversion.
I didn't understand a lot of his engineer jargon but the dumbed down explanation was phones operate inside that frequency range so anything outside of that causes problems and normalizing the file removes the drastic ups and downs in the volume helping stay out of cell phones noise cancelling tech.