for 3 months after moving into a second-floor victorian conversion flat in London, I couldn't sleep.

every single night around 2:15 AM, a physical sensation would wake me up: not an audible sound in the traditional sense, but an overwhelming, nauseating low-frequency pressure vibrating directly through the wooden mattress frame into my ribcage. It felt like living inside the engine room of a container ship.

whenever I asked my landlord or the upstairs neighbors, they looked at me like I was insane. 'It’s completely quiet outside. You can’t hear a pin drop.'

I am an audio engineer by trade. I don't guess when it comes to physics.

last tuesday at 2:30 AM, when the vibration started again, I set up my measurement rig:
- Calibrated earthworks M30 measurement microphone positioned at ear level in the bedroom center.
- Focusrite clarett interface running into an Realtime audio analyzer with 1/24th-octave resolution.
- 3-axis accelerometer sensor taped directly to the primary structural floorboard.

data there was undeniable: a massive, razor-sharp +18dB acoustic spike locked precisely at 38.4 Hz, also, accompanied by harmonic overtones at 76.8 Hz and 115.2 Hz

human hearing threshold drops significantly at low frequencies, which is why older neighbors didn't 'hear' it as a tone and they just felt unexplained anxiety and poor sleep, while my trained ears were detecting the standing wave resonance in our 4-meter room dimension.

took the acoustic report, then walked down to the basement commercial unit (a 24-hour convenience grocery that opened four months ago), and knocked on the manager's door.

sure enough, yada yada, in their back storage room, they had installed a commercial walk-in refrigeration compressor and it was, well, bolted directly into the structural brick chimney breast with zero vibration-isolation neoprene pads or spring decouplers. so at 2:00 AM, when ambient city traffic dies down, the entire building masonry was acting as an acoustic loudspeaker tuned to 38Hz

handed the environmental health officer my certified RTA frequency logs. the grocery store was issued an immediate statutory noise nuisance abatement notice and had to install elastomeric isolation mounts within seven days.

since Friday, the 38Hz peak has dropped by 22dB. The room tone is dead flat. I slept eight hours unbroken for the first time in ninety days

if you feel unexplained nighttime vibration or pressure in an older building: maybe-perhaps you are not going crazy just yet as physics always leaves a measurable signature around

Hello.

Just finished setting up the room. Speakers arrived today so I placed them as the layout suggests.

I asked Claude where to put the panels and below is its suggestion. Help a brother out please thanks! 😁

**Room:** 4.0 × 3.5 × 2.5 m dedicated 2-ch listening room (speakers on the 4 m wall). Sonus faber Sonetto V G2 + NAD C 399 w/ BluOS-D (Dirac Live, ≤500 Hz). Rug + 12 mm rebond underlay, loaded bookshelves on rear halves of side walls, heavy curtains on the window wall.

**Panel schedule (6 panels, all rockwool, 60 × 120 cm, fabric-wrapped, cleat-mounted with 3–5 cm air gap, portrait):**

**Sequence:** Dirac baseline → hang front + side panels → re-measure → hang rear → re-measure → export new filters.

**Not yet:** bass traps. Room's 43–49 Hz modes are handled by Dirac for now; corner treatment (superchunks or a sub for the seat null) only if the post-panel measurements say so.

I built a mobile REW-light application to make measuring quicker and easier.

The app is called CarSweep. I originally built it to tune the DSP in my car (because convertibles are absolute acoustic nightmares), but the math is the same, and it can be used in a AV-System just as good.

Here is what it does:
Log Sweeps & FFT: Plays a sweep over Bluetooth, records it, and calculates the actual frequency response at your listening position.

UMIK-1 Support: The built-in iPhone mic is fine for a quick check, but if you own a miniDSP UMIK-1 (or similar USB mic), you can plug it into your iPhone and import your specific .txt mic calibration file for accurate measurements. (Experimental)

Real-Time Analyzer (RTA): Streams continuous pink noise with a live 1/3-octave spectrum (Fast, Slow, and Moving-Mic averaging) so you can adjust your hardware EQ/DSP in real time.

Parametric EQ Generation: Calculates concrete parametric EQ values based on your target curve, which you can export as a JSON preset or manually dial into your DSP.

It’s a hobby project, so there is no subscription. The base app is free, completely offline, and has no ads or trackers. There is a single one-time purchase to unlock the Expert features (UMIK-1 support, custom curves, expanded 20Hz-20kHz range) just to help cover my costs.

If you are a regular REW user, I’d love for you to measure your listening room with both and tell me how my curves compare to your laptop setup. Feedback is hugely appreciated!

Just put together a small 2.1 setup in my home office. Running a Cambridge Audio CXA81 mkII to a pair of Klipsch KG 4’s. and a REL HIT1003 sub. Source is a Eversolo dmp a6 gen2. Just waiting on my new Crites tweeters and crossovers and I’ll be done for now (lol!) Really liking the sound from this setup so far.

Was annoyed for years regarding the DoP limitations, as it cuts the max DSD rate by half what I can use on my MacOS. So I asked claude to come up with a workaround which allows the player to talk to the DAC directly. Let me know what you think

https://github.com/xenide/dsd-rust/pull/6

Anyone know of any good online courses that teaches about acoustics treatment/engineering/design?

So I just picked up an RME 802 FS AE and I’ve been experimenting with its built in Room EQ feature. After several hours of testing in REW this is my best result.

The purple trace is with no eq just a high/low pass at 80hz. The blue trace is the fully EQed result.

My biggest issue is right around 80hz. I was able to get my left speaker and left sub to integrate perfectly but my right speaker seems to produce a massive null around 80 hz all on its own even without subs.

The massive peak right next to the 80hz null is also coming from my right speaker. When I combine the left and right subs together with the right speaker it results in that double null on either side of 80hz.

I tried literally every combination of polarity and phase in my svs subs. I took measurements from 0-180 degrees phase in 10 degree steps with polarity set to both positive and negative and then set the subs to the result that integrated best but no matter the phase or polarity I couldn’t completely eliminate the null and this was the best I could do.

I was able to eliminate the null and peak in the right speaker by running no crossovers on the subs or speakers at all but the it would come back after applying eq.

EDIT: This is a 2.2 system with dedicated L+R subs positioned symmetrically next to their corresponding speakers.

Hello Everyone Today I’m selling mine Micro Precision 3.28 MK II Tweeters currently looking fir an offer anywhere b/w 250-270$

Supreme sells some incredibly high end products. The space is simply gorgeous, they accept one client at a time and the whole space is dedicated to them. These are Odeon horn speakers from Germany, with Air Tight amps. One of my favorite experiences since I got into this hobby 3 decades ago

We’ve all got tracks we reach for when trying a new pair of speakers, testing a change in placement or hearing someone else’s system.

I’m putting together a reference playlist, but I want it to be more useful than another list of well-recorded audiophile favourites. For each track, I’d like to document what it actually tests and what someone should listen for.

If possible, pease share:

Track, Artist
What it tests: imaging, bass extension, dynamics, vocals, separation, treble, etc.
What you listen for: what does a good system get right and what tends to go wrong?

I recently found an amazing pair of Paradigm Atom V2s. They’re in great condition, work like intended, and were only $80, only issue is the person I bought them from must’ve been a chain smoker because they smell so strongly of cigarette smoke. They’re for a smaller room and I really don’t want it to suddenly develop a tinge of cigarette from these speakers. Any tips on how to make them not smell so strong? I’ve just been trying to air them out in a big room but I suspect that’ll take a while…

my setup so far. ive got them plugged into Paradigm Reference Studio 80s (which ill need to take a photo of once i get home). Before anyone asks yes i do have the dust cover i just like keeping it off while playing 😁😁

I was gifted this Micro Seiki turntable from a friend; it turns on and seems to work well (He hadn't used it in 15 plus years), it does need a new cartridge.

I would love to actually use it but not sure if I can afford to restore it properly.

It is so beautiful, I still can't believe it mine.

Not sure how to proceed, any advice would be appreciated.

Can anyone recognize the receiver in this photo. I know it’s blurry , it’s a screenshot of an old photo. Early to mid 70’s is what I was told. Thanks

I mean, if your speakers are playing something loud and the power suddenly goes out, that can't be good, right?

Hi all, what is the best way to to calculate how much acoustic treatment is needed for a large hall (500+ people)? Is there a way to calculate what type of material would be needed for the acoustic treatment, how much is needed, where it should be placed, etc.

My initial thought was to use REW and based off of some calculations using the Sabin equation, it could help me determine how much treatment is needed, and then to create a design of the hall using EASE 5. Would this be the correct approach?

Speakers are a close second in terms of improving the sound (Yes I know room treatment is first but will get to that eventually).

I ordered one with the Umik 1 and it cost me £350 altogether. I wanted it more specifically for my dual subs that were connected to my Wiim Ultra's sub out via a y splitter. I watched guides on YouTube on how to time align, gain match and do PEQ etc, and man it was exhausting but totally worth it. The bass sounds so much better than before, as I hadn't realised how muddy/boomy it was. The bass now just blends in with the speakers so well. There is more tinkering to do but for now I'm very happy.

Because I am using the Wiim Ultra for the speakers, I just used roomfit with the Umik 1 instead of REW, as it was easier to do. However, when I get the time and patience I will use REW.

Hi all

I’ve been clearing out some boxes and I found this old amplifier - I believe it’s an Audio Innovations Alto AM1. I tested it and it works great but it’s not in the best condition with some scratches, faded/rubbed off letters and two missing knobs at the front

(16 and new to that stuff)

Hey !
I built my first sound system
2x lonely th12
Kick planar
HS28T

I try to Learn how to find good parameters

I did

Processor (DSP): the t.racks 206
System Type: 4-Way Active Sound System (Sub, Kick, Mid, High)
Crossover Points:
Sub: ~30 Hz (HPF / Subsonic) to 89 Hz
Kick: 89 Hz to 210 Hz
Mid: 210 Hz to 1.1 kHz
High: 1.1 kHz and up

Out 1 (Sub): ⁠0.00 ms⁠
Out 2 (Kick): ⁠0.42 ms⁠
Out 3 (Mid): ⁠2.99 ms⁠
Out 4 (High): ⁠3.06 ms⁠
With alignement method someone recommended that

Out 1 (Sub): ⁠+2.0db
Out 2 (Kick): +1.5
Out 3 (Mid): ⁠-11.0 dB⁠
Out 4 (High): ⁠-17.0 dB⁠
(My top is too powerful compared to my kick and sub’s

For the EQ
I measure Sub and Kick on the ground (someone recommended that also)
For Med and High at ear level

Sub):
PEQ 1: Freq = ⁠58 Hz⁠ | Gain = ⁠-4.0 dB⁠ | Q = ⁠18.6⁠
Out 2 (Kick):
PEQ 1: Freq = ⁠102 Hz⁠ | Gain = ⁠-11.5 dB⁠ | Q = ⁠9.3⁠
PEQ 2: Freq = ⁠109 Hz⁠ | Gain = ⁠-10.6 dB⁠ | Q = ⁠10.5⁠
PEQ 3: Freq = ⁠171 Hz⁠ | Gain = ⁠-7.1 dB⁠ | Q = ⁠11.6⁠
Out 3 (Mid):
PEQ 1: Freq = ⁠400 Hz⁠ | Gain = ⁠-11.0 dB⁠ | Q = ⁠1.0⁠
Out 4 (High):
PEQ 1: Freq = ⁠2738 Hz⁠ | Gain = ⁠-11.0 dB⁠ | Q = ⁠1.0⁠

What do you think ? Any advice for the drop at 3khz ?

Thx very much !

As of right now most of music files are m4a 128kbps lossy. I would enjoy higher quality audio I just wonder if it's worth it. And if it is, any tips one apps I can download higher quality music from online for free or a low cost. If this isn't the right subreddit, please help me find the right one. Anything helps. Please and thank you.

I need to open up my old A3CD for maintenance. I am was the first owner and have never had it open. The screw head looks sort of like a mangled torx or "6 lobe," but again, unless they mangled it at the factory, that's not it. Anyone know what kind of scree this is? TIA!

La musique a toujours été une passion pour moi.

Mais je n'avais jamais vraiment écouté de la musique sur du bon matériel. Avec une bonne qualité de son.

J'ai décidé d'investir et j'ai depuis 3 jours un Wiim Amp Pro et des Warfedale Diamond 12.1i.

J'ai pris une grosse claque. C'était magnifique.

Mais ce soir j'ai une impression étrange.

Comme s'il m'en fallait plus.

Comme s'il fallait encore mieux.

Comme si je n'étais pas rassasié.

Est-ce que c'est pour ça que des gens mettent des sommes folles dans du matériel ?

Est-ce que j'ai été contaminé ?