Integrating Subwoofer with 2 channel system

Polkitup2

I decided to try a subwoofer with my two channel system and took some measurements of the frequency response of my Tyler Linbrook Monitors and Polk Micropro 1000 using the realtraps test CD http://www.realtraps.com/test-cd.htm. After I got the sub dialed in as far as matching phase with the Tylers and finding the optimal room placement, and crossover, I think i got it to blend quite well with the exception of one dip in frequency response.

I ran the test first with just the Tylers and then with the Tylers and the Micropro 1000. I used the line level inputs with the Micropro crossover set at 60 Hz. Initalliy I was a little disappointed at the SPL levels I was able to get from the Micropro using my Musical Fidelity A1 but I can see from the chart and from listening that I am in fact getting substantial support from the Micropro in the lower frequencies - plus 10 db in some areas. In the chart, frequency is shown on the x axis and SPL level on the y axis. Interesting cancellation dip around 50 -55 Hz.

lightman1

Polkitup2 wrote: »

I decided to try a subwoofer with my two channel system and took some measurements of the frequency response of my Tyler Linbrook Monitors and Polk Micropro 1000 using the realtraps test CD http://www.realtraps.com/test-cd.htm. After I got the sub dialed in as far as matching phase with the Tylers and finding the optimal room placement, and crossover, I think i got it to blend quite well with the exception of one dip in frequency response.

I ran the test first with just the Tylers and then with the Tylers and the Micropro 1000. I used the line level inputs with the Micropro crossover set at 60 Hz. Initalliy I was a little disappointed at the SPL levels I was able to get from the Micropro using my Musical Fidelity A1 but I can see from the chart and from listening that I am in fact getting substantial support from the Micropro in the lower frequencies - plus 10 db in some areas. In the chart, frequency is shown on the x axis and SPL level on the y axis. Interesting cancellation dip around 50 -55 Hz.

Looks like they're fighting each other at 50-55Hz. Have you tried flipping the phase on the sub and finding another spot in the room? FWIW.

Ern Dog

Nice work Polkitup2. The sub is doing a nice job with the low end. I have 2 suggestions: try changing the crossover to around 50hz so that the sub would start after that nasty dip instead of before it. The second would be to turn up the volume on the sub a tad to get a flatter response.

Polkitup2

I did some initial testing and got the loudest SPL using a phase of 0 but further testing indicates that SPL and phase are dependent on the frequency. I tested all four phase positions of the sub and as shown in the chart, they all produce different results. They all seem to have their drawbacks. I think it's interesting how the dip that I saw initially seems to get pushed to lower frequencies when the phase was changed. Anybody care to pick which phase would be best?

Polkitup2

Ern Dog wrote: »

Nice work Polkitup2. The sub is doing a nice job with the low end. I have 2 suggestions: try changing the crossover to around 50hz so that the sub would start after that nasty dip instead of before it. The second would be to turn up the volume on the sub a tad to get a flatter response.

Excellent suggestion on setting the crossover to 50 and I am currently runnning the volume at 30 out of 40 so I am not sure how much higher I can realistically go.

Polkitup2

I upped the sub volume to 33 out of 40 and set the crossover at 50, it seemed to move the dip to the left.

Polkitup2

Same test as above but with phase set to 90. Big dip, I can see there is no easy answer here so I am going to set phase to 0, set sub volume to 33, and set the cross over between 50 and 60 and be done with it.

rallyshark

That's pretty cool! Even I can understand. It's good to see a graph with before and after the sub. It looks like the micropro starts to fall on its face around 30hz. If only it could hold that 10db boost to 20hz! Still a nice improvemet though. More importantly, how does it sound to your ears? Does it integrate well with all your music? Is it musical, or a little boomy? Just curious:)

Polkitup2

It does integrate well and sounds excellent. Base is tight, no boom, and frankly, before I produced the charts I wasn't exactly sure what it was doing for me. Which I guess is good since the sub is not drawing attention to itself. Although there were peaks and valleys in the charted frequency response, I don't notice them. It provide's low end support where the Tylers alone were a little weak. For example bass runs in Jazz are more pronounced and it seems to fill out the sound more than the speakers alone could do. I also noticed that I now listen at a lower volume. Before the sub I think I had to turn things up a bit to get the low end I was looking for which made vocals a bit louder than I liked.

lightman1

What was your final setting on the sub set up?

Polkitup2

Phase to 0, sub volume 33/40, and the crossover between 50 and 60. I may try some other setting when I get a chance, maybe move the sub to the other side of my system.

danz1906

Polkitup2 wrote: »

It does integrate well and sounds excellent. Base is tight, no boom, and frankly, before I produced the charts I wasn't exactly sure what it was doing for me. Which I guess is good since the sub is not drawing attention to itself. Although there were peaks and valleys in the charted frequency response, I don't notice them. It provide's low end support where the Tylers alone were a little weak. For example bass runs in Jazz are more pronounced and it seems to fill out the sound more than the speakers alone could do. I also noticed that I now listen at a lower volume. Before the sub I think I had to turn things up a bit to get the low end I was looking for which made vocals a bit louder than I liked.

Congrats on getting it Right-Enjoy:D

Polkitup2

Well almost right, with some further tweaking I have determiend the optimal settings for my room are a crossover of about 50 -60 Hz, a phase of 270, and aligning the sub driver in-line with the Tyler speakers. This yielded the curve below.

Ern Dog

That is a nice improvement. Now Enjoy it.