[texanater]

I recently acquired the ultimate analog test lp, and for shiggles tried it live.  There is a test that steps down from 1khz to 20 hz in a total of 30 steps.  On the 15th step which I calculate is about 200 hz, the amplitude drops off quickly by ear.  On the 19th step which I calculate is about 130 hz the volume reaches a minimum.  It sounds up to 10 db off but that is truly a wild assed guess.  I have no way of actually measuring the real amplitude.  The volume begins to come back as the frequency drops.  So, in short there is a significant volume drop between 200hz and 100hz with a min near 130hz. I do not hear the drop when I listen through my headphones. Is this normal?  The speakers sound great and I never noticed this with regular music.  I tried the test on a set of Rogers LS2 and noticed a similar yet much less pronounced behavior. I guess it could be room interaction, but the same drop off occurs regardless of speaker placement.  Very confusing.  Thanks for your thoughts!

[texanater]

I should add that I have a toddler who is fascinated with them and I'ved already had to replace 2 tweeters.  There may be some other damage I can't see. Further, I'm not the most skilled wood worker and could have messed up the cabinets.  Lastly, I stuffed a little bit of foam in the cabinets, not much but some.  Maybe that is affecting things.

Thanks again!

Nate

[Danny Richie]

Sounds like room related effects.

Also, the cabinets are best off lined with No Rez and then a loose fill of polyfill or fiberglass insolation behind the woofers.

If not lined with No Rez then a dense layer of polyfill or fiberglass insolation should be used to cover the entire inside leaving only a clear air path to the port.

[texanater]

Thanks Danny,

The cabinets are lined with No Res and I added some egg crate foam in the empty area.  It sounds like you are saying there should be a clear air way from the drivers to the port.  Is that right?  Should I remove the egg crate foam?

Room interaction seems reasonable, but its a pretty large 2 story room.  I haven't measured it but its ~12' wide by 20' long by 18' high with a sloping roof.  Does that sound susceptible to loss in the 100-200hz range?

Thanks!

Nate

[Danny Richie]

The cabinets are lined with No Res and I added some egg crate foam in the empty area.  It sounds like you are saying there should be a clear air way from the drivers to the port.  Is that right?  Should I remove the egg crate foam?

Yeah, I would pull the egg create foam out. That is probably over doing it.

Room interaction seems reasonable, but its a pretty large 2 story room.  I haven't measured it but its ~12' wide by 20' long by 18' high with a sloping roof.  Does that sound susceptible to loss in the 100-200hz range?

Yeah, the high sloping roof will cause measurement problems. It may not sound bad as the added reflection is heard as a delay, but from a measurement standpoint it will cause cancellation.