Advertisement



  1. Things you need to know about the new ‘Conversations’ PM system:

    a) DO NOT REPLY TO THE NOTIFICATION EMAIL! I get them, not the intended recipient. I get a lot of them and I do not want them! It is just a notification, log into the site and reply from there.

    b) To delete old conversations use the ‘Leave conversation’ option. This is just delete by another name.
    Dismiss Notice

Room measurements - what do they mean?

Discussion in 'audio' started by killie99, Mar 13, 2021.

  1. killie99

    killie99 pfm Member

    Got hold of an XTZ Room Analyser II Pro and I've ran some basic measurements, now what? What's deemed 'good enough' and what's 'oh my god your room is crap'?
    I did notice that moving the microphone only a small distance (4 or 5 cm's) can make quite a difference to the resulting graph.
    Anyway, here's my graphs.
    Any helpful input appreciated.

    [​IMG]

    [​IMG]

    [​IMG]
     
  2. Purité Audio

    Purité Audio Trade: Purite Audio

  3. killie99

    killie99 pfm Member

    room is 458 x 385 x 236 - Amroc says node at 37.5Hz, XTZ measures it at 39Hz.
    To measure each speaker I guess I only plug in left channel from the XTZ box, measure, only plug in the right channel, measure. I don't see anything in the software that allows me to select a single channel.
     
  4. Fatmarley

    Fatmarley "It appears my intelligence circuits have melted"

    I wonder if the reason I haven't had any low frequency problems for a long time now is because my hif is now in the bedroom, and the king-size Ottoman bed (full of clothes) acts like a big bass trap.
     
  5. RJohan

    RJohan pfm Member

    Generally I think the curve is typical for speakers in a ordinary listening room and, honestly, I've seen worse. The lower mid and up seems quite even.

    DON'T try to do anything about the treble, it's common for it to loose energy in room measurements.

    If you don't like to use an equalizer to even out the ca 39 Hz maxima you should try moving the speakers and/or listening position around.

    The 85 Hz and 115 Hz minimums is harder to do with an EQ, it probably comes from phazing out's from room boundaries near the speakers. Moving the speakers around might help here.
     
  6. RJohan

    RJohan pfm Member

    Yes.
     
  7. Purité Audio

    Purité Audio Trade: Purite Audio

    Which speakers are you using Killie?
    Keith
     
  8. killie99

    killie99 pfm Member

    Monitor Audio PL300
     
  9. Old Shatterhand

    Old Shatterhand pfm Member

    No, it won't. If you don't use speakers that don't play very deep for example a Harbeth P3ESR (even then) you will have bass problems as in every untreated room. Every room follows the rules of physic, it doesn't matter if it is a big or a small room only the frequencies that are resonating are shifting.

    @All:
    Note: Most users think their room is okay because the don't know what a "good" room is. I can't count the times when people are telling they don't have any room problems (not directed to you!).

    If the room isn't treated via BIG foam bass traps (we are talking in meters, not centimeters), passive membrane absorber, Helmholtz-resonators, plate-swingers, active bass traps you won't get any "real good" bass out of any room.

    DSPs do harm, even if some people tell you the opposite. They lower the amplitude of the music signal but don't solve the room problem. They also have ringing artifacts like pre-ringing and (FIR-filter) or post-ringing (IIR-filter) and both ad phase distortions. Post-ringing isn't that easy to detect because it is more or less masked by the music signal.

    Nonetheless, IMO you can hear the negative accompanying phenomenons and I was distracted by that. The music sounded artificial to me but maybe other users are more distracted by the bass bumps and other stuff.
     
  10. Purité Audio

    Purité Audio Trade: Purite Audio

    These,
    https://www.stereophile.com/content/monitor-audio-platinum-pl300-ii-loudspeaker-measurements
    The treble is unusual, usually it just goes down as frequency increases, what is the rest of the system, do you have the capability of implementing EQ to the 40Hz peak?
    If you download REW you can input your room’s measurements into its ‘room simulation’ feature, then you can virtually move your speakers and your listening position which will point to the positions which give the flattest response.
    Keith
     
    Last edited: Mar 13, 2021
  11. Fatmarley

    Fatmarley "It appears my intelligence circuits have melted"

    I didn't get the same quality of bass at a show compared to home, but obviously the room was a different shape/size. I get good bass down to about 25hz/30hz in my bedroom, so quite a bit more extension than Harbeth P3ESR I'd imagine:

    [​IMG]
     
  12. killie99

    killie99 pfm Member

    They’re series 1 PL300’s. Amp is a Neurochrome Mod 686, pre is a Salas DCG3.Going to have a go at measuring each speaker individually .....
     
  13. ToTo Man

    ToTo Man the band not the dog

    @killie99, the broad treble droop @12kHz is probably because you're measuring both speakers at the same time. Measuring each speaker individually should give you a more accurate picture of what's going on in the mids and highs.
     
  14. ToTo Man

    ToTo Man the band not the dog

    Love the 120dB scale, didn't notice it until I got my magnifying glass out! ;)
     
  15. ToTo Man

    ToTo Man the band not the dog

    Excessive ringing in the time domain is more harmful to musical enjoyment IME than a peaky low-frequency amplitude response, and is fortunately relatively easy to improve with modest amounts of passive acoustical treatments.
     
  16. AudioAl

    AudioAl pfm Member

    I normally use a tape measure in feet and inches , Still can't get my head around that strange foreign cm mm mtrs stuff

    Oh sorry not that kind of measuring :rolleyes:
     
  17. killie99

    killie99 pfm Member

    Here's the speakers measured as left and right:

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  18. Fatmarley

    Fatmarley "It appears my intelligence circuits have melted"

    10db steps isn't that bad. I've seen people on here upload 20db or more steps. I suppose it would a lot more helpful if everyone used the same scale though. When I'm doing gated measurements of my speakers, away from boundaries, I try to use the same scale and graph size as Stereophile.

    Most importantly, they sound fine at low frequencies to my ears, with no boom, exaggerated, or subjectively slow sounding bass. I see that as a pretty good achievement for a speaker that goes down to 25hz.
     
  19. ToTo Man

    ToTo Man the band not the dog

    @killie99 , Yep, your high frequency response looks normal now so nothing to worry about there. If the peak at 40Hz is bothering you and is the axial mode caused by the length of your room (i.e. wall behind speakers to wall behind listening seat), then you can ameliorate it either by moving your listening position further away from the rear wall, moving your speakers further away from the front wall, or a combination of both. In my room I prefer my speakers closer to the front wall and my listening seat further out from the rear wall, as I find this controls my 40Hz peak without increasing SBIR. Moving your listening seat away from the rear wall should also allow you to hear more direct sound from the speakers and less room contribution, which you may or may not prefer.
     
    John Phillips likes this.
  20. Purité Audio

    Purité Audio Trade: Purite Audio

    The left and right peaks coincide, the question is can you hear that peak at around 40Hz is there a brrrrrrrrrr you can use REW’s ‘generator’ filter start at 30Hz and increase to 40Hz you should be able to hear the reinforcement, don’t play one frequency for too long or for too long, walk around the room, there should be much more base against the front and rear walls.
    Keith
     
    Getgaff likes this.

Share This Page





Advertisement


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice