Digitrax decoder sound quality

I recently installed a Digitrax SDXH166D sound decoder into a Life Like Proto 200 GP9. The unit runs fine, slow speed is smooth and the horn and the bell sound good. But the prime mover sound is barely audible. I have CV 58 set to factory spec and I’ve adjusted the prime mover volume CV all over the range with no change. It is unsatisfactory. I was just wondering if any of you have had a similar problem with Digitrax decoders and if this is a common problem or what?

WHat sound file did you load? SOme are better than others - some take advantage of the extra features the X version of the decoder has over the same one without the X in the nane, others are universla nd can work in any of the decoders, which means at most they can use only the feautures of the older decoders.

All in all, you basically get what you pay for, a low cost soudn decoder isn’t going to be as good as one of the top tier ones like Loksound, Tsunami 2, or WowSound.

ALso, you may have to turn down the horn and bell, crank the prime mover, crank the master volume, and then adjust the horn and bell.

–Randy

I tried both the GP10 and GP38 that are in the decoder. And trust me, I’ve had those volume CVs all over the place.

In my experience, the Digitrax decoders have good sound but lacking a bit in power. A really good speaker and enclosure are vital - if possible, a 1" speaker is best.

But as noted, different sound projects have different properties. With some you can get away with a smaller speaker like 1/2" x 1". I’d check out all that are available - IIRC there are several F-unit projects available, their sounds should work for a 1st generation GP.

I’ll remember that, I’m thinking of a Digitrax sound decoder for my F7 a-b powered passenger train, for the economics. This would be my first sound install.

Mike.

What speaker did you use?

The speaker that is hard wired to the decoder. It’s an oval 16 x 26 mm and has a built in hard plastic baffle.

I didn’t know it came with a speaker. In a recent video, Larry Puckett had a negative comment on oval speakers. I have no personal experience on ovals. One thing I did learn, which isn’t your problem, is that at least some TCS decoders can overpower and blow out a sugarcube speaker.

Here’s the decoder and speaker.

http://www.digitrax.com/products/sound-decoders/sdxh166d/

Thinking of this one myself. Half the price of a WowSound, but, you get what you pay for.

Mike.

I get that. I bought this one from an on-line retailer so I didn’t pay the MSRP listed but it wasn’t what I would consider cheap either. I’m late to the party when it comes to getting into DCC and converting my DC locomotives has certainly been a disappointing experience so far.

I don’t have the Digitrax SDXH166D in any of my locos, but I did spend all weekend adjusting the various volume controls on my locos that are equpped with Tsunami or QSI. So, let me offer my most recent experience.

First of all, while the Digitrax sound decoder may be less expensive than other sound decoders, I would initially proceed on the assumption that the cost factor should make no difference as far as volume is concerned.

Second of all, I would initially proceed on the assumption that the speaker is not defective. Maybe that will turn out to be the problem, but for testing purposes, assume that the speaker is just fine. That said, the decoder instruction sheet does note on page 4 that the speaker mounting and baffle can greatly affect sound performance.

Third of all, regarding sound files, although that decoder offers 7 different choices, the factory default is set to zero so the Sound Scheme Select (CV 60) has been disabled, resulting in generic sound.

In testing my locos over the weekend, I had pencil and paper at hand to note the various CV settings that I was testing since the various volume controls are somewhat interrelated. Begin testing with a decoder reset to factory defaults (CV 8 = 8).

Then start with the Master Volume control (CV 58). The factory default is 9 over a zero to 15 range. So, the maximum volume of other controls is limited to 60% of the maximum capacity. Change the setting to CV 58 = 15. Reset the bell (CV 141) and horn (CV 142) to zero to mute those sounds. Now, start adjusting the Prime Mover volume control (CV 140) with a very low value, say 5. The factory default is 60 within a range of zero to 64. Test the sound volume at CV 140 = 5. Then, reset the sound volume at CV 140 = 60, the factory default. The prime mover volume should be significantly louder.

Let us know if that works.

Rich

Rich,

All good information, thank you. I would think if the speaker were the problem, or it were damaged, it would affect the bell and horn too. Those sound fine.

I sent a message to the Digitrax “Help Desk” and part of their response was: “The prime mover in this sound file is relatively quiet.”

To which I would replay; Who wants a “relatively quiet” locomotive?

They also suggested that I set CV60 to 3, which is the GP10 sound file, and set CV 140 to 64, which is the max. I did both and it made no difference.

The bottom line here? I will never buy another Digitrax decoder.

Have you checked the value of CV 58 which is the Master Volume control?

If all else fails, why not email the Digitrax Help Desk again and tell them that you did what they suggested but that the PM volume is still barely audible?

Rich

Try another sound file, one that actually uses the capabilities of the X series. Those built in ones (3 of them - consider the GOOD projects use all the memory for ONE loco). Look for one that explicitly says 16 bit, and particularly ones made by John McMasters. The GP38 and GP10 schemes that come with the decoder are 8 bit, not 16 bit, and are of much lower quality than the decoder is capable of. They are included so you don’t get a blank decoder with no sounds and wonder if it is DOA.

IN general, the horn SHOULD be louder than the prime mover. A weak horn quieter than the prime mover no matter what you do is why I got rid of the one Tsunami I tried and never bought another. The first Tsunami 2’s didn;t sound any better, but more recent ones, it seems liek maybe they have updated the recordings a bit. Too late, I’m strictly ESU now.

–Randy

Thanks. Found one for the F7.

Not hijacking OP, just riding along. [swg]

Mike.

Yes, Digitrax suggests a value of 4 or 5 and i’ve tried it there and every where up to the max 15. No result.

As for replying to Digitrax again, not sure it would do any good. I got the impression from their firstanswer that this is working as it was supposed to.

And where do I find that and how to I get it into the decoder?

Well, I guess that there is not much more to say at this point. If the prime mover is barely audible, and Digitrax thinks that is as it should be, dunno.

Rich

In the Sound Depot on the Digitrax web site. You need a PR3 or PR4, and the Soundloader software to load sound files. Most vendors will load your choice before shipping the decoder, otherwise you will need to find someone with the proper hardware.

Most of them listed have sound clips to play so you can hear what they sound like.

–Randy

I just watched a YouTube video in which an Atlas employee demonstrated a GP38 with an ESU sound decoder. That prime mover was awfully loud. No idea what Digitrax may be thinking.

Rich