@oldhvymec ha, don’t worry the mic is at my head position. You’ve definitely got me thinking though of some creative ways to absorb the boundary issues on the left side where the windows are. On the right speaker because it’s an open room there’s no boundary issues there.
Showing 13 responses by hudsonhawk
Definitely aware of the back wall reinforcement, however the room isn’t big enough to allow moving the couch forward more than a few inches. I’m also aware that probably limits how much improvement I can realistically make here.
Don’t get me wrong, I’m worried about the suck outs as well - it’s funny, I generated a tone at 55hz after noticing that cavernous drop on the graph and confirmed it’s completely missing in the listening position, and reappears as soon as you move around the room. Room modes are funny things.
That said the humps are the more glaring problem since they have such long decay time they end up sounding super muddy and boomy.
Try miking your speakers like 1' away and see if your 120 Hz bump is still there. If so, it may be a microphone artifact@erik_squires Yep, still there even mic’d directly in front of the speaker. So to oldhvymec‘s point it could be a crossover issue or a mic artefact like you said. Unlike the other ringing in the waterfall I’m not hearing it, so I’m inclined to think it’s a mic artefact. Would love to do the same with bass traps but I think I’m already pushing my wife’s tolerance for panels.
@oldhvymec to your point, pulling them out does reduce the bass suck, but makes the peaks greater and makes the midrange less flat. Here’s an SPL graph of them pulled out (red) vs their current position closer to the wall (orange): https://www.dropbox.com/s/4rd8y9uy7jw12lb/Screen%20Shot%202021-02-22%20at%2010.06.16%20AM.png?dl=0
I have 10 GIK panels in the room right now, in retrospect the mistake I made was getting too many 2” panels and not doing enough bass traps or ceiling panels. They’re crazy expensive but one of the things that appeals to me about the PSI AVAA is that they’re easily moved and don’t require a ton of work to install.
The tough thing about renting is not wanting to overinvest in a solution for your current place, in fact our lease is up in a few months and we’re currently considering moving. I’m tempted to just to get a better room for my stereo, where I won’t need to have the LP be against a wall...
Great suggestions all, thanks for the thoughts.
@tomeh45 there’s no manual for the Kivas, but I did talk to Jim at Egglestonworks and he not only had some tips for me, he was kind enough to cut some port plugs for me for the slot loaded bass port. For the transmission line ports, they’re pretty heavily diffused internally so they aren’t super loud, but just to reduce interactions further I have the GIK bass traps hung behind them so they are absorbing anything from them.
Audio2design pretty much nailed the layout, but here’s the floorplan in case you’re curious about the exact dimensions. Ceilings are 8 foot:
@oldhvymec You know it’s funny, I didn’t think I had a problem with mids until I moved them into the current position (the orange line) and you can see that those deep troughs in the MB region improved significantly and it was like lifting a veil.
Agreed on curtains, the other problem with that room is that it’s asymmetrical so you have the windows on the left and then an open kitchen on the right. Maybe I need to get out of this nightmare room and move...
@jimofmaine it never occurred to me until I started getting into measurement and understanding room modes that a reason to get subs is to have more flexibility in placement of where the bass is being generated.
@millercarbon she absolutely had her priorities straight and there was no way I would have ever convinced her to swap places. Sadly she passed away recently but she lived a long life and enjoyed my hobby a lot as it gave her lots of lap time, although like many from her generation she preferred digital to analog (because I never had to get up to change the record).
@speakermaster Great question and a detail I forgot to mention is that i did decouple the speakers by adding Isoacoustics Gaia feet to the speakers. It didn’t make as big of a difference for the bass as I was hoping (although in retrospect I wish I’d measured before and after, I didn’t yet have the measurement mic) but it did improve the imaging significantly.
The odd thing is that 120hz didn’t seem to be there when there’s no signal. This weekend I’ll do some more measuring, there’s been a lot of good hypotheses about what it could be. I’ll run a test tone at 60hz to see if it’s a harmonic, more mic’ing of the room with no signal playing to see if it’s environmental, and with different sources to make sure it’s not an artefact being produced by my DAC or integrated amp.
@rego placement is the correct way to solve this, unfortunately the speakers are quite large and the room allows limited movement of the listening position or the speakers themselves.
Good news is I got in touch with PSI and am in the process of arranging for an in-home trial of the AVAA C20, which could be a good, if expensive, solution to my troubles.
I’m also planning on a few other measurement trials this weekend with different placement of my bass traps, this thread’s given me a ton of ideas thank you all for your thoughtful responses.
So an update here: nearfield measurement shows the speakers, unsurprisingly, have an almost flat response.
And massive kudos to those who said the 120hz spike was a harmonic - you win a prize for that one. When generating a 60hz tone, the spike at 120hz is visible on the analyzer. Very interesting!
For now, I’ve been able to do a little EQ’ing to address the problem, at least with music played from my music server. Interestingly I didn’t really like the results when using a convolution curve in Roon - it reduced the bass way too much - and I ended up just using Roon’s parametric EQ, using the room’s graph for reference.
Longer term, I’m arranging a demo of the PSI AVAA C20, and waiting to see what happens with our lease before deciding between that and more bass traps.