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Genelec 8351B Review (Studio Monitor)

YSC

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This is exactly what I was describing - deep nulls from cancellation. Moving the sub around the room (or your MLP) will shift that null away from the MLP and at worse may move a peak to the MLP (which can be mitigated with EQ).
if you can go with some distortion bass nulls can be pulled by EQ to some degree though
 

Pearljam5000

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Love it in white
Screenshot_20220221-061539.jpg
 

sarumbear

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This is exactly what I was describing - deep nulls from cancellation. Moving the sub around the room (or your MLP) will shift that null away from the MLP and at worse may move a peak to the MLP (which can be mitigated with EQ).
How about using bass traps?
 

YSC

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You can not fix decay times with out bass trapping and that is more important than the nulls.
of course, treatment with EQ is the way to make one perfect, but when room treatment isn't viable, bumping the nulls to make a good bass FR with lingering decay/resonance at the original null sounds better IMO, I did mine and the bumping with 3-5% distortion measured (presumably due to decay) did sound better than raw
 

807Recordings

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of course, treatment with EQ is the way to make one perfect, but when room treatment isn't viable, bumping the nulls to make a good bass FR with lingering decay/resonance at the original null sounds better IMO, I did mine and the bumping with 3-5% distortion measured (presumably due to decay) did sound better than raw
of course we all know pumping into nulls also increases the problem but I guess you also mean removing some extra energy on the peaks. Not knowing the situation I will not comment if it is viable or not the acoustic treatments. I live in a small space and even have some in the living room with a walnut finish to add the ugly white sterile walls.
 

YSC

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of course we all know pumping into nulls also increases the problem but I guess you also mean removing some extra energy on the peaks. Not knowing the situation I will not comment if it is viable or not the acoustic treatments. I live in a small space and even have some in the living room with a walnut finish to add the ugly white sterile walls.
yes, I mean flattening the peaks to fit the preference curve below the schroeder frequency. for myself the not viable is that I am in a cage room in Hong Kong, if I dare put anything thicker than 1cm I would have to remove myself, or remove the chair, that's how tight it is (I can't also gain some fat or I will have by belly squeezing into the table;))
 

807Recordings

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yes, I mean flattening the peaks to fit the preference curve below the schroeder frequency. for myself the not viable is that I am in a cage room in Hong Kong, if I dare put anything thicker than 1cm I would have to remove myself, or remove the chair, that's how tight it is (I can't also gain some fat or I will have by belly squeezing into the table;))
I can feel for you on the space issue as even my move to Berlin has drastically reduced my space compared to what I used to have in Dresden, not to mention Canada. :)
 

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I can feel for you on the space issue as even my move to Berlin has drastically reduced my space compared to what I used to have in Dresden, not to mention Canada. :)
you have to visit Tokyo or Hong Kong to really visuallize the situation, the common apartment space for a family is... 300 square foot, and thus my entertainment (gaming and hifi) room is like 3.5m*1.5m, that's excluding all the wardrobe, documents, figures etc. with Genelec 7040 barely fits under the desk right next to the corner and leave some room for my leg.

On the plus side, the sensible volume to listen without wife or neighbour come for some civilized discussion of noise makes bumping the bass at 50hz by 9db to be only 3% distortion in the 7040. so I can fill in all bass nulls from room modes, and seems all sort of trash placement did make the reflection manageable to really make bumping bass doable, a few rounds of EQ and re-measure confirms a 6db boost in EQ resulted in 4.5db rise in actualy FR
 

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sarumbear

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Bass traps adequate to reduce bass below 80Hz is pretty large!
That is true but it flattens the FR in all locations not just the listening position like you can by moving the subwoofer around. I want my family and friends to enjoy my system too :)

Also, you can easily integrate a bass trap into the fabric of the room. It is not difficult to smooth the corners with DIY floor to ceiling bass traps.
 

Spocko

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That is true but it flattens the FR in all locations not just the listening position like you can by moving the subwoofer around. I want my family and friends to enjoy my system too :)

Also, you can easily integrate a bass trap into the fabric of the room. It is not difficult to smooth the corners with DIY floor to ceiling bass traps.
Actually, only multiple subwoofers (let's say 4) plus bass management EQ (Dirac Live for instance) will give even bass for more seating positions beyond your MLP. With only 1 subwoofer, you'll never have even bass outside the single MLP - room modes will always be a problem somewhere
 

pozz

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Bass traps adequate to reduce bass below 80Hz is pretty large! For example, to absorb between 75 Hz and 110Hz, GIK's largest Monster Bass Trap is already 7 inches thick (see image below). So to control 60Hz it would be prety THICK - 16 inches is what people are doing, see this discussion: https://www.avsforum.com/threads/ethan-to-the-rescue-with-60hz-dip-please.2086546/post-36240106
View attachment 188540
These are not the best examples of bass traps: https://www.audiosciencereview.com/forum/index.php?threads/bass-trap.23870/post-802732 Although GIK does offer a panel option for the Monster series.
Actually, only multiple subwoofers (let's say 4) plus bass management EQ (Dirac Live for instance) will give even bass for more seating positions beyond your MLP. With only 1 subwoofer, you'll never have even bass outside the single MLP - room modes will always be a problem somewhere
Not exactly. If you want a source, Toole (partly humorously) refers to moving subs around as "positional EQ" in his book. You can optimize the placement of a single sub, definitely.

Here's an example from an acoustic consultant: https://redspade-audio.blogspot.com/2020/05/why-you-dont-need-two-subs.html The consultant says he always recommends just one sub. Perhaps his customers are limited by budget. I personally would buy four big ones, but the sad part is that I only have one, and only a few positions to put it in. So I tamed what I could with EQ and for now am ready to wait a while before the next purchase. Hopefully, hopefully, acoustic metamaterial will common enough outside of industrial applications to use at home.
 

ernestcarl

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The consultant says he always recommends just one sub.

Actually he said half the people needed only one, the other more. Not all setups require multiple subs. First thing to do is to find out if you really need more since some of the clients had multiple subs that didn’t really help at all with their situation.
 

Sancus

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If you really wanna use treatment to affected low bass(quite a bad idea if you're not literally building a studio IMO) I think you're likely better off using frequency tuned membrane traps or active absorbers instead of padding your whole room with 16" of rockwool. That said it'd be interesting to do comparisons of all these techniques, I still don't see what the benefit is supposed to be over multi-sub.

Obviously you do need some absorption to get reverb times down but that's very little compared to trying to "bass trap" your way out of room modes.

The consultant says he always recommends just one sub.
I'm becoming increasingly suspicious of claims you only need one sub as long as you're only optimizing 1 listening position. It would be interesting to measure a variety of rooms, but in my room the response is *quite* different in the same chair between leaning forward, sitting straight, and reclining. And I can't imagine being restricted to one specific position while sitting -- that's not comfortable or relaxing. Head in a vice indeed.

It wasn't really possible to fix all those positions with just 1 sub and EQ. 2 made it a lot easier. And I don't understand the argument that 1 can sometimes make things worse. Maybe those people just aren't familiar with proper multi-sub optimization techniques, but I don't think it's mathematically possible for 2 properly optimized subs to produce a worse response than 1 under ANY circumstances.
 
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FrantzM

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If you really wanna use treatment to affected low bass(quite a bad idea if you're not literally building a studio IMO) I think you're likely better off using frequency tuned membrane traps or active absorbers instead of padding your whole room with 16" of rockwool. That said it'd be interesting to do comparisons of all these techniques, I still don't see what the benefit is supposed to be over multi-sub.

Obviously you do need some absorption to get reverb times down but that's very little compared to trying to "bass trap" your way out of room modes.


I'm becoming increasingly suspicious of claims you only need one sub as long as you're only optimizing 1 listening position. It would be interesting to measure a variety of rooms, but in my room the response is *quite* different in the same chair between leaning forward, sitting straight, and reclining. And I can't imagine being restricted to one specific position while sitting -- that's comfortable or relaxing. Head in a vice indeed.

It wasn't really possible to fix all those positions with just 1 sub and EQ. 2 made it a lot easier. And I don't understand the argument that 1 can sometimes make things worse. Maybe those people just aren't familiar with proper multi-sub optimization techniques, but I don't think it's mathematically possible for 2 properly optimized subs to produce a worse response than 1 under ANY circumstances.
+1

Thanks for posting this... I am of the same opinion. My experiences, observations and conclusions mirror yours.
 

807Recordings

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Although bass trap size is a factor here and GIK Monster traps work well, especially if you go for the limp mass membrane that further targets bass frequencies there is other options like VPR. As the poster said there is no space and if he needed something acceptable it would have to likely be custom. I like my GIK panels but some day in my dreams when I build a house I would go fully custom and have all speakers hidden and sofit mounted. Just walk into a room watch a movie/tv and be blown away by the sound.

Once you have a well tuned room it is pretty hard not to want one as the sound is so addictive.
 

sarumbear

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Actually, only multiple subwoofers (let's say 4) plus bass management EQ (Dirac Live for instance) will give even bass for more seating positions beyond your MLP. With only 1 subwoofer, you'll never have even bass outside the single MLP - room modes will always be a problem somewhere
I think you are wrong. Room modes can treated passively (bass traps) as well as actively (subwoofers). You may want to learn more on what can be done using acoustic treatment. After all, room modes are fixed to the geometry of the room and hence predictable very easily even before the audio system powered-up.

Meanwhile, you see bass traps to be inconvenient as they are big but seem to ignore how much space four subwoofers will take in a room.

In short, there are two methods to treat a room: passive or active. Choose the one you like but do not think that one is superior than the other as that is not true.
 
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sarumbear

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I like my GIK panels but some day in my dreams when I build a house I would go fully custom and have all speakers hidden and sofit mounted. Just walk into a room watch a movie/tv and be blown away by the sound.

Once you have a well tuned room it is pretty hard not to want one as the sound is so addictive.
I agree with you.

I have bass traps built into the corners and into the ceiling when my house was built. I have an M.A. in acoustics and was able to advise the architect. I use in-wall speakers for my HT but use floor-standers for my music room. Both rooms are treated for standing waves and RT60, especially flutter echo by not using any parallel walls.
 
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