[tremrej65]

Here's my setup and feedback of my rounded version of the DT sub.
Link to the build: https://www.audiocircle.com/index.php?topic=191642.0

Setup and feedback
First, the feedback.
I’ve been listening to it for over a month now, and I like it. Really like it.
When I was listening to my X-LS Encore as is, without sub, I was questioning myself on why I was building a sub: I really liked the overall balance of the X-LS Encore: the bass is present, very fast, textured and precise. I was a bit afraid of losing that by adding a sub. Where the X-LS Encore was struggling was the extreme bass. That level of bass is present only on a very few pieces of music I listen to. Was it worth the risk? Oh yes it did. The sub enhances the whole presentation of the music, any music.
I added a high pass filter tuned at 70 Hz (68.9 to be precised) on the amp to the X-LS Encore. The sub gives me extreme bass, and the filter gives me more sound level pressure ( I can drive X-LS Encore louder now that it doesn’t handle the extreme bass). And I didn’t lose any precision of the bass. The bass is actually better, more precise, super textured like I never heard before.

The setup:


I use GR Research speaker cable (24 strands)


The filter:


The response:


The setup, how I did it.
Here, nothing new to most of you I guess. For me, I learn a lot.
I use REW software on a Windows laptop with a USB measurement microphone from Hifiberry.
I first measured the X-LS Encore with the high-pass filter. Then I measured the sub.
To tuned the phase of the sub, I used a 70 Hz mono tone signal that I sent to the sub and main speaker simultaneously. I use a SPL meter with REW. I tuned the phase to get the most SPL. The best setup was only two click from zero, i.e. very small adjustment.
Then I played with the different setting of the sub amp to get as close of a flat response I could get.
The rest will have to be tuned with room acoustic treatment. I’ll update you once I get there (not before few months).

The setting of the amp:



That's it for now.
Back to listening to some music...
Rejean

[Glady86]

I had a huge dip centered at around 70hz, Close to the frequency of the rolloff.  Even though I think the output was a tad higher at zero phase,  moving it to 180 degrees out of phase fixed the hole without affecting the other bands much. Using REW, I couldn’t see a difference in measurement with small movements of phase. It sounds good to me, but will try more measurements and tweaking to see if any better performance is possible.