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Thread: Harbeth Monitor 40.1 specific

  1. #141
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    Default Re: Harbeth Monitor 40.1 specific

    Hi Jeff,
    Wonder if you tried your stand without sand? In my limited experience, sand fiilled stand tend to let bass, especially for speakers which need stand, to sound more solid or "obvious".

    Cheers...

  2. #142
    Jeff Day Guest

    Default Re: Harbeth Monitor 40.1 specific

    Quote Originally Posted by keithwwk View Post
    Hi Jeff,
    Wonder if you tried your stand without sand? In my limited experience, sand fiilled stand tend to let bass, especially for speakers which need stand, to sound more solid or "obvious".

    Cheers...
    Hi Keith,

    Thanks for the reminder. I had intended to remove the sand and see if that would help, but got distracted and forgot about it. I'll have to do that soon.

    Best,

    Jeff

  3. #143
    Jeff Day Guest

    Default Re: Harbeth Monitor 40.1 specific

    Quote Originally Posted by keithwwk View Post
    Hi Jeff,
    Wonder if you tried your stand without sand? In my limited experience, sand fiilled stand tend to let bass, especially for speakers which need stand, to sound more solid or "obvious".

    Cheers...
    Hi Keith,

    I removed all the sand from my Skylan stands, however, it didn't really make a meaningful difference, so I shall keep trying to figure out what to do.

    Best,

    Jeff

  4. #144
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    Default Re: Harbeth Monitor 40.1 specific

    Can you describe the furnishing, positioning and absorption of the room in which you have these speakers please? As you may have read, I started a thread here recently about optimising the listening room, and hence the listening experience.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  5. #145
    Jeff Day Guest

    Default Re: Harbeth Monitor 40.1 specific

    Quote Originally Posted by A.S. View Post
    Can you describe the furnishing, positioning and absorption of the room in which you have these speakers please? As you may have read, I started a thread here recently about optimizing the listening room, and hence the listening experience.
    Hi Alan,

    Thanks for asking, I appreciate your thoughtfulness in trying to help me sort things out.

    My listening room is approximately 20 feet wide, 29 feet long, and the ceiling is of variable height from about 10 feet to 20 feet. The floor is carpeted, and the room is treated with 3 Acoustic RWL-3 Acoustic Conditioner panels in the rear corners and one sidewall (http://www.positive-feedback.com/Iss...tic_revive.htm).

    The speakers are about 110 inches apart, 55 inches from the side walls (measured at the speaker side), and about 55 inches from the wall behind them (measured at the rear of the speaker). The speakers were set up according the method described in Jim Smith's book Get Better Sound where you adjust speaker position to give the most natural string bass sound (Ray Brown's bass was used).

    It's probably easier to show a couple of room photos than describe it, so please see the accompanying photos.





    Best,

    Jeff

  6. #146
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    Default Rate your own room ...

    Hello Jeff,

    First I'd like to thank you for sharing your room with us and second, congratulate you on a generously proportioned, beautiful and inviting environment. There is a thread here, unrelated to your enquiry, which (when completed) may give some general pointers that could be useful to you and others. Please can I have some feedback from you: after reading the entire thread, could I ask you to rate your living room for acoustic absorption on a scale of 0-10, with 0 being a cave and 10 being an anechoic chamber.

    I know your answer will be a generalisation, but I'd very much like to know where you put it on an acoustic scale. We're not concerned here about cosmetics (full marks for that!), solely acoustic absorption. You can get a good feel for the acoustics even with your eyes closed. What I do when entering an unknown acoustic environment is to walk around clapping my hands as loudly and crisply together as I can to get a real sharp sonic impulse. This builds a mental picture of the overall sonics of the room - at least in the middle and upper frequencies. Quickly evaluating the low frequencies is more tricky because there isn't enough energy in the hand clap to excite the LF: for that a starting pistol or large firework would be ideal! (Don't try that at home please!)
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  7. #147
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    Default Re: Harbeth Monitor 40.1 specific

    Jeff,
    Congrats on a beautiful room and setup! One thing I noticed is that your speakers are the same distance from the back wall to the side walls. Theoretically, at least, this could lead to Allison effects that may be causing the some of the boom you're getting. Just something to consider.

    Eric

  8. #148
    Jeff Day Guest

    Default Re: Rate your own room ...

    Quote Originally Posted by A.S. View Post
    Hello Jeff,

    First I'd like to thank you for sharing your room with us and second, congratulate you on a generously proportioned, beautiful and inviting environment. There is a thread here, unrelated to your enquiry, which (when completed) may give some general pointers that could be useful to you and others. Please can I have some feedback from you: after reading the entire thread, could I ask you to rate your living room for acoustic absorption on a scale of 0-10, with 0 being a cave and 10 being an anechoic chamber.

    I know your answer will be a generalisation, but I'd very much like to know where you put it on an acoustic scale. We're not concerned here about cosmetics (full marks for that!), solely acoustic absorption. You can get a good feel for the acoustics even with your eyes closed. What I do when entering an unknown acoustic environment is to walk around clapping my hands as loudly and crisply together as I can to get a real sharp sonic impulse. This builds a mental picture of the overall sonics of the room - at least in the middle and upper frequencies. Quickly evaluating the low frequencies is more tricky because there isn't enough energy in the hand clap to excite the LF: for that a starting pistol or large firework would be ideal! (Don't try that at home please!)
    Thank you for the kind words, Alan, appreciated. I'm not so sure about a subjective rating, but before answering your question I evaluated my room using an RT60 analyzer via a signal played through the M40.1s, and got a reverb time in the mid 300ms range, which is a typical reading for a studio.

    That surprised me a little, as I thought the room was more live than that. However, the acoustic panels in the room, combined with the wall fabric hangings, and the carpeted floor probably do deaden things quite a bit.

    Best,

    Jeff

  9. #149
    Jeff Day Guest

    Default Re: Harbeth Monitor 40.1 specific

    Quote Originally Posted by Eric Pitschmann View Post
    Jeff,
    Congrats on a beautiful room and setup! One thing I noticed is that your speakers are the same distance from the back wall to the side walls. Theoretically, at least, this could lead to Allison effects that may be causing the some of the boom you're getting. Just something to consider.

    Eric
    Thanks for the kind words Eric.

    Hmmm ... interesting comment. I spent quite a lot of time moving the speakers around to different positions in the room using the afore mentioned Jim Smith method, and that particular placement position actually gave the most natural sounding bass, with the least amount of bass emphasis.

    Like all things audio, it seems things can get inexplicably weird at times! :-)

    Best,

    Jeff

  10. #150
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    Default Re: Harbeth Monitor 40.1 specific

    According to the Allison theory, and assuming the centre of your woofer is 22" from the floor.

    If you want to maintain your speakers 55" from the side wall the distance to the rear wall should be 138".

    If you want to maintain your speakers 55" from the back wall then the distance to the side wall should be 34.79"

    As I recall the formula is the square root of the product of the shortest distance and the longest distance calculates the other dimension. Usually the woofer to the floor is the shortest.

    All measurements should be from the centre of the woofer.

  11. #151
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    Default Re: Rate your own room ...

    So, Jeff, ignoring the test gear and using your own judgement, I'm still looking for a numerical score from you! Just curious.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  12. #152
    Jeff Day Guest

    Default Re: Rate your own room ...

    Quote Originally Posted by A.S. View Post
    So, Jeff, ignoring the test gear and using your own judgement, I'm still looking for a numerical score from you! Just curious.
    Hmmm ... subjectively I would put it at about a 5 I suppose using your analogy, Alan.

    Best,

    Jeff

  13. #153
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    Default Re: Harbeth Monitor 40.1 specific

    Jeff,
    I apologize in advance if I've missed this, but have you taken frequency response measurements of your system? That would show you where, frequency-wise, where the bass problems are.

    Another thing to consider is some sort of room correction. I have the M40.1's in a room much smaller than yours (11' x 17' with 8' ceilings) and use a Behringer DEQ2496 betweeen my transport and DAC, so it's only used in the digital domain. I find it very useful in minimizing midbass boom in my room. I use the Behringer ECM8000 mike with it, which isn't perfect, but is good enough for bass measurements.

    You may be wondering, "didn't Alan design the 40.1's to work in rooms without having to use EQ?" Just to put things in perspective, the EQ is needed for my M30's in this room as well, so some rooms are just problematic.

    Regarding the Acoustic Revive panels, are they desinged to ameliorate bass problems? From reading their description, I did not see much talk about the bass region. You may want to consider trying dedicated bass traps. I have two pairs of the Cathedral Sound panels in each upper corner. I can't honestly say they made a huge difference. My before/after measurements did not yield much difference, but it did sound to me that the lower midbass was cleaner and had more "punch."

    Keep us posted... It would be a shame if you felt you had to part with the M40.1's - they are fantastic speakers!

    In my room, I had to do more experimenting with placement of the M40.1's than I was expecting, but am now at a stage where I'm really enjoying them. I think with a bit more experimenting, you can arrive at that happy place, too,

    Eric

  14. #154
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    Default Re: Rate your own room ...

    Umm. I'm not so sure about that. I think that half way between a cave and an anechoic chamber with a score of about 5 would be a well designed, sweet sounding concert hall. Such a room would have an excellently well controlled decay across the entire band, no 'hot' frequencies which seem to hang-on after the note and would never draw attention to itself.
    So, I think we have to be realistic and say that the beautiful room you listen-in must be somewhat less damped than a '5' rating would honestly justify. Almost all domestic rooms have far, far less absorption than ideal for listening to hi-fi minus the room's overarching contribution. And that really is the nub of the problem. There are three ways forward ....

    1. Increase the damping and hence absorption in the room, perhaps significantly and accept that the acoustic treatment is going to impact on the cosmetics - which just may not be acceptable and/or

    2. Change or somehow modify the speakers themselves to pump less bass into the room and/or

    3. Introduce some electronic adjustment in the signal path (of the amp) to reduce the amount of drive to the speakers in regions where the room's absorption is lower than ideal.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  15. #155
    Jeff Day Guest

    Default Re: Rate your own room ...

    Quote Originally Posted by A.S. View Post
    Umm. I'm not so sure about that. I think that half way between a cave and an anechoic chamber with a score of about 5 would be a well designed, sweet sounding concert hall. Such a room would have an excellently well controlled decay across the entire band, no 'hot' frequencies which seem to hang-on after the note and would never draw attention to itself.
    So, I think we have to be realistic and say that the beautiful room you listen-in must be somewhat less damped than a '5' rating would honestly justify. Almost all domestic rooms have far, far less absorption than ideal for listening to hi-fi minus the room's overarching contribution. And that really is the nub of the problem. There are three ways forward ....

    1. Increase the damping and hence absorption in the room, perhaps significantly and accept that the acoustic treatment is going to impact on the cosmetics - which just may not be acceptable and/or

    2. Change or somehow modify the speakers themselves to pump less bass into the room and/or

    3. Introduce some electronic adjustment in the signal path (of the amp) to reduce the amount of drive to the speakers in regions where the room's absorption is lower than ideal.
    That's why I don't like talking in subjective terms when talking about rooms, Alan, as it really doesn't tell you anything meaningful - it's better to use measurements. For example, as I'm sure you know due to your BBC experience, the optimum reverb time for music is considered by most people to range from 0.2 seconds to 2.6 seconds depending on the venue. 0.2 to 1.2 seconds is considered by most to be a 'dead space' and 1.2 to 2.6 seconds is considered to be a 'live space'.

    A typical studio measures from 0.2 to 0.6 seconds, a good venue for classical music measures 1.2 to 1.6 seconds, a good venue for chamber measures from 1.4 to 1.8 seconds, and so forth. My room measures with a reverb time of about 0.35 seconds from 32Hz to 16K Hz, which means it is a 'dead space' by measurement, and falls in the range typical of studios. So even though you are assuming that it is a live space by looking at the photos, the measurements don't really support that conclusion.

    What is unusual is that the M40.1 is the only speaker out of the many I've had through here that exhibits exaggerated bass response in the room, so it leaves me a bit puzzled. I'm not saying I don't like the M40.1, Alan, I like it very much, except for the somewhat elevated bass response I'm getting.

    I think you are correct though, Alan, the M40.1 may very well need equalization to achieve the best performance in domestic environments. As far as suggestion 1 goes, I think the room measurements show that is not the issue. However, I am interested to hear your thoughts on suggestion 2, and while it is easy to do 3 for digital, to do analog EQ for the whole system doesn't seem practical, and really it shouldn't be necessary to have to resort to that.

    Kind regards,

    Jeff

  16. #156
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    Default Room reverb

    In my room, getting the M40s on taller (24") stands helps the bass response significantly (and I think others have found this with the M40s). I know Alan made adjustments to the M40.1s that allow for lower stands, but it might be worth a try to get them about 24" off the floor just to see if the difference in bass response is more to your liking.

  17. #157
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    Default Room reverb

    Hi Jeff,

    Did you use the reverb calculator as featured in the link below to calculate the reverb time of your room?

    http://www.csgnetwork.com/acousticreverbdelaycalc.html

    It is interesting to note that your room measures as a "dead" space with a reverb time of 0.35s. From the pictures of your room it doesn't really look too dead. The reverb time you've got in your listening space is even lower than that of a typical studio if the figures are averaged out. I suspect the carpet floor has got a lot to do with the excessive absorption, more so if you've got thick padding underneath. Also, the material of your walls, presumably drywall constructed from sheetrock is slightly (maybe considerably) more absorbent than concrete or masonry walls. I agree that it is more useful to carry out measurements to give a more meaningful interpretation of the acoustical conditions of the room.

    May I know the source that has been referred to in the description of room acoustical conditions(dead/live/studio/chamber etc.) based on reverb time?

    Since you have gone to the extent of measuring the reverb time of your room, I suspect you must have done some measurement on the frequency response of your speakers using an RS meter and some test tones? After plotting out the graphs you would have a better idea how the variations in tones would look like. Subsequently you can fine-tune the position of the speakers to achieve the smoothest bass response. Anyway since you mentioned you already followed the setup guidelines of Jim Smith and spent a lot of time moving the speakers around, guess that wouldn't help much.

    Eric may have a point in the Acoustic Revive panels of not being effective in addressing bass problems. They may not be designed for the purpose as the thickness of the panels will have insignificant impact in trapping bass frequencies. Proper bass traps will reduce bass energy by decreasing the null and bringing down peaks at the same time. It may be worth a try apart from recommendations of a taller speaker stand since various speaker positioning have not worked out for you.

  18. #158
    Jeff Day Guest

    Default Room reverb

    Hi Ryder,

    I didn't use a web based calculator, but rather an RT60 anyalyzer and measured reverb decay time for each octave band, 31Hz - 16kHz, by pulsing pink noise on and off through the M40.1s, filtering the incoming signal by octave band, and measuring the timing of the decay of each octave band. My room doesn't look very dead, but it measures quite dead. I actually wouldn't mind if it were a little more live, say in the 1.4 second range.

    There's quite a lot of information about optimum reverberation times out on the web for different sorts of venues, just try searching on 'optimum reverberation times' on Google and lots of useful links will come up.

    There's some nice examples at http://www.acousticalsolutions.com/sounds.asp . I've attached a handy reference chart from the same site that shows ranges for optimum reverb times for various music venues.

    Best,

    Jeff
    Attached Files Attached Files

  19. #159
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    Default Room reverb

    Thanks for the response Jeff. Is the reverb time of 0.35s an average or a consistent figure across the entire frequency band? If you wouldn't mind, can you try out the web-based calculator in the link to determine whether the results you have obtained with your RT60 analyzer are consistent with the one provided on the web? I am curious to know as I find the values of the reverberation time to differ greatly across the frequency spectrum. Thanks in advance.

  20. #160
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    Default Re: Harbeth Monitor 40.1 specific

    On a separate note, I have noticed that the speaker stands are not spiked to the floor. Have you tried spiking the Skylan stands to the floor? Or the stands are designed to be placed flat on the floor without spikes?

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