Your Opinion on Smoke and Sound

[Atlantic Central]

Ray and all,

I will make one more comment about sound, even in small scales like HO.

IF, one is running ONLY one locomotive at a time, on a simple single theme layout, there is something to be said for sound, dispite its generally poor fidelity. In such a case, the viewer is only focused on that one train/locomotive with no distractions from other trains or activities.

That is a dramaticly different situation when compaired to a large layout with multiple trains and lots of action. On a large layout with multiple trains, even turned down to their lowest levels, sound equiped locos quickly turn into a din.

So for a small single train layout, I can understand the desire for sound.

But not for me with six-eight trains moving at once.

Sheldon

[CNE Runner]

Sheldon, you definitely make a good point. I only run one locomotive at a time - so I am able to preserve what little sanity I have.

Ray

[rogertra]

As Sheldon said, sound has "poor fidelity", I say it sounds like a 1960s tinny transistor radio.

As for HO smoke, fine if you enjoy the toy like look of the stuff and don't mind wiping the residue from your track and structures.

[Joe Satnik]

Dear All,

It's hard to put sound into a "Yes-No" answer.

Human hearing is complicated.  I don't like sound if it tires my ears.  Tired ears make you turn off your sound. 

"High Fidelity" sound tires ones ears much less than "Low Fidelity",

which is what most model train sound systems are, especially in the smaller scales.

Lets say I wanted to make my sound really crappy.  I would have terrible mis-matches in the equalization department, for example, use a 1/2 inch diameter speaker in an N scale tender, and expect to get bass out of it. 

The human ear wants to hear a nice bass roll-off balanced with a nice treble roll off, with a reasonably flat midrange in between. 

Here is a balanced (double-ended) roll off formula:  bass roll-off frequency X treble roll-off frequency = 400,000. 

For example, my speaker system highs roll off at about 8 KHz.  Where should my bass roll off?  400,000/8000 = 50 Hz.

(It takes a significant sized box and speaker (driver) to get to a 50 Hz roll-off.)

Telephone highs roll off at about 3kHz.  Where should the bass roll-off be?  400,000/3000 = 133.3 Hz.

The problem with most small scale speakers is too much treble (a very high roll-off), a spiky midrange, and  no bass.

A woofer under the train table would work well, but the signal would somehow have to be coordinated with the speaker in the loco or tender. 

Let's say I want to make my sound even crappier.  In order to save memory (and thus money) I would digitize it with really slow sampling rate, and use very few bits of precision in the Analog to Digital (A/D) conversion of the original Analog signal. 

Now the playback of the digitally stored signal is a "Low Fidelity approximation" of the original signal.  The distortion introduced (by the cheap digital storage/playback system) may not be apparent to you, but it tires your ears.   

As time goes on, memory chips get more and more capacity, and the cost/byte keeps going down, so saving memory space is not as much a concern... I predict less sampling/digitizing distortion in future sound chips.

Hope this helps.

Joe Satnik

[Joe Satnik]

Another source of distortion is a recording engineer who doesn't know what he's doing. 

Most common is over-driving the microphone and pre-amp with too loud a sound from the prototype, e.g. a loco's whistle, which causes "clipping" distortion. Volume must be limited.

The highest frequency allowed in the digital recording is a little less than half the sampling rate.  Frequency must be limited to avoid "aliasing" errors/distortion.

You may wake up now. 

Sincerely,

Joe Satnik     

[Johnson Bar Jeff]

Smoke and sound? I don't need either.

Of course, I generally run "vintage" rolling stock, from before sound was available, so in that sense it isn't an issue, but I still don't need them.

My first HO locomotive was a Revell 0-6-0T that smoked; I remember that I could never see the smoke, though my dad and my grandpa both swore that they could. Smoke just seems like a toylike gimmick to me.

[Jhanecker2]

I am not that big a fan of smoke & noise . Worked in machine shops & manufacturing too long. If I have a need for either one I go to play with my power tools or fire up my sound system , four or five hours of heavy metal usually does it for me. Besides which running the trains is loud enough indoors , and outdoors I have UP single track line literally across the street ( formerly CNW).  I hope we get Metra service someday , I would love to run into Chicago without driving ; it takes about an hour one way . J2