First subwoofer build - feedback needed

[Sigberg Audio]

View attachment 543088

It's making noise! I finally cobbled together a few cables, hooked it up to my soundcard and did a few measurements (in room) in 0-100Hz range using REW. Then applied 3 filters to EQ out the worst room modes and got this response in my listening position.

View attachment 543089

Then I took another, full range measurement to figure out how to match levels of the sub and my main speakers and finally measured this:
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I'm sure there's a lot of room for improvement but I'm quite happy already. Now that I've got a calibrated mic I'd like to measure the sub alone, but I need to do more reading about how it's done properly.

To make it easier to read the graphs, try to stay with the common X/Y-windows

Try to keep the Y-axis of your graph at 45-105dB at all times.

For showing bass, have the X-axis at 20-200hz.
For full range, have the X-axis at 20-20,000hz.

And use the tab called "All SPL", not "SPL & Phase".

Beyond that, it looks like the gain of the sub could be increased by at least 5dB.

 

[66o_]

Thanks for the tips @Sigberg Audio! I did more reading on sub integration last night and I just finished a set of measurements.

Sub + Right speaker, no eq, crossover at 80Hz (LR24) done in totalmix

Then that's how they sum up (L+R+Sub) after phase alignment and two notch EQs to fight the room modes

There's still a dip at 80Hz but I believe it's a room mode (78Hz) rather than incorrect crossover summing. I'm still pretty new to all this so I might have made mistakes when taking measurements and setting everything up, I'll give it a few more tries in the next days, it's fun!

What's important is that the system sounds pretty good and I actually prefer my sub to 7350A, mostly because I feel like I have way more control over the amount of bass (I tend to keep it low).

Next steps:
- I still want to check how little space I can leave behind the driver before I start hearing vent noises, that's the next item on the list
- then I'm planning to build the final enclosures (2pcs)
- once I have two subs I want put together a dsp unit based on the DSPi and move the crossover out of my RME.


Edit: spectrogram, I hope the second sub will help a bit with those room mode at 30Hz

 

[Sigberg Audio]

It's possible to get that 32-33hz peak down more with EQ probably?

 

[thewas]

Quite nice, I wouldn't worry as much about the 80 Hz dip as about the dip you have between approximately 100 and 150 Hz due to the response and possibly placement of your "satellites", I would experiment there with EQ or different placement to reduce it.

 

[66o_]

Quite nice, I wouldn't worry as much about the 80 Hz dip as about the dip you have between approximately 100 and 150 Hz due to the response and possibly placement of your "satellites", I would experiment there with EQ or different placement to reduce it.

Actually, it was the sub - the response was dropping off way too quickly after 80Hz due to room mode. I moved the crossover frequency 70Hz and moved the sub slightly further away from the corner which made its response in 80-100Hz range a bit smoother. Here's the final result.

Thanks for all the advice btw, I really appreciate it! I'm done with tweaking for now - it's a temporary setup anyway. I'm moving onto getting the sub as thin as possible, then building another one. Once I have two subs the endless setup and measurements can start again