My room has "zero" slap echo. Do I need room treatments?

most walls are 8" by 8" logs

No one else seems to have caught this. Logs are curved, in other words your entire wall is essentially a diffuser panel. Sound hits the curves and is scattered. That’s why you hear no slap echo.

This is however a bit misleading. The sounds that are scattered are in a frequency range related to the curves of the logs. You can calculate this, or you can experiment and hear it. What you will find either way is the sound is really well dispersed at the high frequency range represented by the diameter of the logs. The typical log in other words that curves out one to three inches diffuses frequencies that are around 3kHz or about what you hear when you clap your hands. Because our hearing is very sensitive at those frequencies. Those logs however don’t do such a great job of scattering lower frequencies. Lower frequencies are longer wavelength and as such the logs "appear" flat to them. Since we aren’t nearly so sensitive to them though they don’t matter as much.

You do not need the stuff the others are talking about. They missed the whole point. Its better to scatter (diffuse) than absorb, as absorption can create a dead closed in sound while diffusion creates more of a sense of space and openness. This is of course a balance, and one only you can decide what is best. Experimentation is always recommended.

Just thought I would point this out as no one else seems to have caught on to the log thong being nearly as relevant as it is.

Good catch millercarbon! And it brings up a question that I've been wondering about; how is the sound quality in a log cabin? Diffusion should be good indeed, although ideally the logs would be arranged vertically rather than horizontally. It might not make that much difference. The walls are probably stiff as can be, not letting much bass out, and probably not resonating much.

cio52, if you bang on the wall with the side of your fist can you get a deep thud out of the log assembly? How does the bass sound in that room?

Thanks for your responses.  To clarify about my room... the horizontal log walls are flat on the inside except for a 1" miter cut at the top and bottom ( so there is about 6" of flat surface and a 2" groove).  If you bang the side of your fist against the wall all you get is a sore fist.  It's really dead sounding.  However, I have seen some log home systems with rounded logs on the inside that would help diffusion and some "post and beam" that were rounded on the vertical.  So, what would work best behind my speakers?

Forgot that you asked about the bass.  I just added two JL Audio E112's to the room and it is incredible what they have done to my whole system's SQ.  As I said above I have a large and very irregular room and needed these subs to pressurize the room to get better sound.  Very happy with the bass.

Using a test tone or more than one test tone and SPL meter you can map out the sound pressure zones in any room. Standing waves, first reflection points and pressure build up in room corners tend to be where the highest sound pressures are measured, sometimes 6 dB or higher than the average sound pressure in the room. Those are where there the treatments should go, generally speaking. Speaker location should be optimized simultaneous.