Sierra Tower w/RAAL in room response question

[Mag_Neato]

Curtis, REW will allow you to set the test sweep to whatever frequencies you wish.

[jimlucci]

Jim...do you run the speakers large or small? Are you sending the frequencies below 80hz to the speakers as well as the sub?

yes. The hk3490 does not have any ability natively to limit freq to the Towers. It has 2 rca outs for the subwoofer connection. It is basic 2 or 2.1 receiver....Jim

[jimlucci]

Curtis, REW will allow you to set the test sweep to whatever frequencies you wish.

I am going to find that option and rerun the phase test again with just a 85Hz tone (which is where I am crossed over on the sub)....Jim

[jimlucci]

You should just run an 80hz tone, if that is where your crossover is set. You don't want anomalies from other frequencies with their room interactions to affect the SPL. 80 hz is where you want the phase to be correct.

Interesting. I did find where you can run a specific pink noise tone at only 85Hz (where my xover is set on the sub). I ran it for 2 minutes with mains and sub all on. I watched the REW spl meter while my Umik1 was in my mlp. The highest spl was at the 0deg and 180 deg (180 being a bit higher), but the 90 deg (middle) was much lower. Very good way to test phase!!

[jimlucci]

and can you run a 10hz to 500hz sweep with just the sub?

Sub only 10 to 500Hz:

subonly.jpg

[Mag_Neato]

Is that with the PEQ filter off?

[jimlucci]

Is that with the PEQ filter off?

Doh! I did have a peq set at 30Hz. Here it is with peq off:

subonly2.jpg

[curtis]

yes. The hk3490 does not have any ability natively to limit freq to the Towers. It has 2 rca outs for the subwoofer connection. It is basic 2 or 2.1 receiver....Jim

So essentially you are not using a crossover, you are just filtering what the sub is playing.

The HK has a pre/out and main/in connections. You should run the pre/out to the sub's line-in, use the sub's highpass filter, and from the sub's HPF out back to the HK's main/ins.

Without a proper crossover, I don't even think you can call the receiver a 2.1.

That said, from your sweep of your mains, it looks like your room has a huge suckout at 70hz. What does the sweep look like one speaker at a time?

[racrawford65]

Unfortunately, it doesn't look like the L12 has an HPF out. So, could run the subpreamp to the Rythmik line-in and use cross-over/phase on the sub. His Towers would still run full range, though.

It's similar to what I do with my Rogue RP5 - run the 1st pair of outs to the amp driving the towers and the second pair to my miniDSP 10x10 (which feeds line in on my E15s). I use the E15 controls for cross-over & phase. My Towers run full range. I could actually cross the Towers if I ran the L/R outputs to the miniDSP and then on to the amp. As I'm mostly vinyl, trying to avoid digitizing as much as possible so I don't do that.

I don't recall if Jim has a miniDSP in his system so not sure if that is a solution without additional cash outlay. He could run the main L/R outs into the miniDSP and then outputs to FL, FR and sub. An alternate to the miniDSP could be one of the dSpeaker products (I think the Antimode is the one for stereo systems).

[jimlucci]

Curtis, you are correct. I am running full range to Towers and Sub and the xover on the L12 sub is just a limiter. Earlier in this thread I posed the question to Dave about inserting a 2X4 Minidsp between between the preamp and amp jumpers on the hk3490 - which I would definitely do if it gave me a benefit. I think he wanted to make sure I had everything else setup before I went down that path.

You are also correct that I have a huge suck out at around 70Hz (and a smaller one at around 200Hz) - I am not sure what that is. It shows up in also when I run the Towers only (Sub off). One of the towers has a pronounced peak/dip in that freq range. The other Tower has a smaller dip at 70Hz that aligns with it.

I am not that familiar with REW results and what would be considered normal. I am also suspicious of the REW tool and/or laptop too. The Towers and Sub all seem to be operating normally. Can room modes and boundaries cause these types of results?

Here are the mains (no sub) individually - left in blue - right in orange.


mainsind2.jpg