Where did my lows go?

[atomicAdam]

So, I though I would be smart, move room with the wife. She had a smaller darker room, I had the larger lighter room. My thinking was that with a smaller room I won't have to turn my music up too so much to enjoy it. I live in a small apt and I don't want to be 'that guy'.

Well, the new room is much smaller. 8ft wide by 11ft long. It can be fully sealed off, well, not air tight, (sorry RnT, cant suffocate), but closed off. The larger room can not.

The speakers are pointed length wise, the floor has carpet, and back wall has a bookshelf. One side has windows with cloth covers, the opposite side has a wall with matched cloth as the window shade. There is some sound proofing foam on the corners behind and to the right of the right speaker and left of the left speaker, but none in the middle. (I found with the foam the sound is much tighter, cleaner).

The sub, when on, not often now, is between the speakers, which are about 4.5ft apart. I sit either close, like 4ft away, or far, 6ft away.

What I've noticed is now with the sub on, there is hardly an extra thump. The speakers go down to 50hz, which in the old room wasn't low enough to hear, but in the new room are fine. But the sub in the new room hardly makes a squeak. It's on, working correctly.

I guess, the question, is it possible to have a room be too small?

I know that comparing the larger room to the smaller room the speakers don't sound as bright and lively. For a couple reason I would image. 1) Less reflection off walls in the larger room, and 2) i sat so far away from the speakers in the larger room it is possible the low frequency sounds just weren't making their way proportionally across the room at lower levels.

Any thoughts on room size? The speakers are just standard Polk RTiA3 bookshelf speakers 5-1/4" Diameter mid range with a 100 watt Onkyo amp and VA Omega III preamp. The sub in an old KEF - prob 6" passive sub run from another Onkyo 100 Watt amp.

Maybe there isn't enough air in the room to move and sound correctly. This concerns me, because the wife wont let me change rooms back, and I've got my eyes set on some larger floor standing speakers in the future.

[JoeE SP9]

Maybe a room that small can't support low frequencies. Just a thought.

[Luvin Da Blues]

Have you tried other locations for the sub? Sounds like you have acoustical cancellation going on at the low freqs.

[atomicAdam]

Have you tried other locations for the sub? Sounds like you have acoustical cancellation going on at the low freqs.

Yes, I've moved the thing around the room. back corners, back middle, front corners, front lower middle. (way below speakers) only place i've not tried it is on top of the bookshelf in the back. nothing seems to help.

[02audionoob]

Does your sub have a phase switch?

[Florian]

Liste to Joe :-)

[This Guy]

Does your sub have a phase switch?

Yeah try switching the black and red wires on that passive sub, although I don't know how much bass a 6" subwoofer would provide in the first place.

[atomicAdam]

Does your sub have a phase switch?


no phaze switch, it is totally passive

[atomicAdam]

Yeah try switching the black and red wires on that passive sub, although I don't know how much bass a 6" subwoofer would provide in the first place.


lol - i've tried that even. thought the wires are set up correctly. guess there just isn't much hope. thanks

[Feanor]

...

Well, the new room is much smaller. 8ft wide by 11ft long. It can be fully sealed off, well, not air tight, (sorry RnT, cant suffocate), but closed off. The larger room can not.
...

Maybe there isn't enough air in the room to move and sound correctly. This concerns me, because the wife wont let me change rooms back, and I've got my eyes set on some larger floor standing speakers in the future.

A room of 11' is inherently incapable of reproducing sound below about 50 Hz, since 11' is the half-wave length of a 50 Hz sound wave. You can try to reproduce deeper but all you'll get is distortion.

[atomicAdam]

A room of 11' is inherently incapable of reproducing sound below about 50 Hz, since 11' is the half-wave length of a 50 Hz sound wave. You can try to reproduce deeper but all you'll get is distortion.


Bingo, that is what I was looking for. Thanks. Now, where did you learn this, or what did you need to know to come to this conclusion.

[Feanor]

Bingo, that is what I was looking for. Thanks. Now, where did you learn this, or what did you need to know to come to this conclusion.

I'm no acoustic engineer, but my understanding is that you can't reproduce a frequency in a space that can't accomodate at least half the wave length of that frequency, that is, a complete positive or negative phase.

The speed of sound varies but is around 1130 ft/sec. The room size is 11 ft. 1130/11 = 102.7 Hz. However that represents the full wave, both positive and negative phases, and you only one phase to reproduce the sound, hence 102.7 / 2 = 51.4 Hz.

I'm not sure the effect of having the other dimensions shorter than 11 ft. You might need two or even all three dimensions >11 ft to produce the 51.4 Hz without distortion, though that's not my present understanding.

[atomicAdam]

I'm no acoustic engineer, but my understanding is that you can't reproduce a frequency in a space that can't accomodate at least half the wave length of that frequency, that is, a complete positive or negative phase.

The speed of sound varies but is around 1130 ft/sec. The room size is 11 ft. 1130/11 = 102.7 Hz. However that represents the full wave, both positive and negative phases, and you only one phase to reproduce the sound, hence 102.7 / 2 = 51.4 Hz.

I'm not sure the effect of having the other dimensions shorter than 11 ft. You might need two or even all three dimensions >11 ft to produce the 51.4 Hz without distortion, though that's not my present understanding.

That seems like a fair assessment of the problem. The Polk speakers have way more lows than they did before, and the bottom out at 50hz.

This means that for the new floorstanding speakers I have in my mind which bottom at 32hz, I am going to be missing some sound. Interesting. Oh well. Thanks Feanor

[02audionoob]

There was a time when I wondered aloud here what defined a small room. The impetus at the time was the reference Dynaudio made to such things in their literature for the Audience line. They published a table of recommended minimum amplifier ratings based on small, medium and large rooms. The Audience 82 can reportedly get down to something like 26Hz, so maybe that's why they made recommendations for it in medium and large rooms, but not small...not being able to accommodate the wave length.

[Kevio]

Nice try but wrong. There is no such limitation (headphones work just fine in much more constrained dimensions).

[atomicAdam]

Nice try but wrong. There is no such limitation (headphones work just fine in much more constrained dimensions).

You know when I went on my run today I thought about the same thing. Just came back here to make a comment and whamp, you beat me to it. Headphone do work on a different power scale so maybe that explains why they work.

If you dont think it is wave length got any suggestions?

[Feanor]

Nice try but wrong. There is no such limitation (headphones work just fine in much more constrained dimensions).

Headphones work directly on your ear channel. They don't need the medium of the room to convey the sound.

[blackraven]

With all things being equal but the room size, wave length is the logical explanation other than the sub is not working correctly. You could try placing the sub back in the larger room to test this.

One last thing, do you have more sound deadening material in the smaller room such as carpet, window treatments etc.?

[atomicAdam]

With all things being equal but the room size, wave length is the logical explanation other than the sub is not working correctly. You could try placing the sub back in the larger room to test this.

One last thing, do you have more sound deadening material in the smaller room such as carpet, window treatments etc.?


I do an I don't. I think I've got the same amount, just in a smaller amount. So, proportionally, yes, there is a larger amount of sound deadening material, but I don't believe it is over done. Spent a couple days testing out foam in different places.

On the room size issue. It is interesting, a 20ft long room would only allow, per say, lows to 28hz.

I'm going to unplug and replug everything back in. One difference is now the Onkyo amp to the sub is getting it's source directly from the pre-amp (it has two lines out). Before it was daisy chained from one amp to another. I'lll try switching back.

Too bad there doesn't seem to be a hard tested scientific case of room size to frequency.

[Kevio]

If you dont think it is wave length got any suggestions?No, I wouldn't hesitate to post if I did. Personally I'd try to EQ it. If that doesn't fix it, it might at least lead you closer to the actual problem.

And yeah, wiring the system the same way you did in the other room would be a good idea ;)

[JoeE SP9]

If the door to the room is on one of the short walls open it completely. If you get better bass you have your answer. If this is the case no amount of Eq of any type will make a bit of difference.

[Florian]

My system has a response (-3db) at 11.5Hz.

In my old room (22ft long) i was missing the very bottom on some pipe organs on Vinyl. In my new room which is 40ft long i get that and more. I believe its the room size also.

[audio amateur]

My room is no more than 12 feet long and I get about 40Hz @ -3dB from my small standmount speakers.

[atomicAdam]

If the door to the room is on one of the short walls open it completely. If you get better bass you have your answer. If this is the case no amount of Eq of any type will make a bit of difference.


no better base - at least not yet - i am going to recheck the wires today - though it is nice and sunny outside - i might have to postpone the wire check and go for a walk

[Feanor]

My room is no more than 12 feet long and I get about 40Hz @ -3dB from my small standmount speakers.

You may feed your system 40 Hz and you might get -3 dB. But here's the catch: you might not be hearing a pure 40 Hz sound. Instead you are getting distortion.

In a rooms too small to reproduce a certain frequency, all that power you're feeding has to go somewhere. It creates distorted sound at a higher frequency than the input signal.

[audio amateur]

You may feed your system 40 Hz and you might get -3 dB. But here's the catch: you might not be hearing a pure 40 Hz sound. Instead you are getting distortion.

In a rooms too small to reproduce a certain frequency, all that power you're feeding has to go somewhere. It creates distorted sound at a higher frequency than the input signal.
I think it's safe to say I can hear the difference between a disorted 40Hz sound and one that is not. A 40Hz sine wave doesn't sound anymore distorted than one of 80Hz, at a reference amplitude. The cone's excursion is well within its limits when I do this. My room seems to produce a peak between approx. 40 and 45Hz which helps to extend the 686's bass. I was quite dumbfounded at first with their bass extention.

'YMMV', as they say around here. But I don't think you're in a position to argue :frown2:
or perhaps I'm utterly wrong and i've forgotten something in the equation..

[atomicAdam]

I think it's safe to say I can hear the difference between a disorted 40Hz sound and one that is not. A 40Hz sine wave doesn't sound anymore distorted than one of 80Hz, at a reference amplitude. The cone's excursion is well within its limits when I do this. My room seems to produce a peak between approx. 40 and 45Hz which helps to extend the 686's bass. I was quite dumbfounded at first with their bass extention.

'YMMV', as they say around here. But I don't think you're in a position to argue :frown2:
or perhaps I'm utterly wrong and i've forgotten something in the equation..

what about diagonal distance? from the bottom left corner to upper right corner.

maybe there is enough distance there to let the wave travel. rooms arent 2D

[JoeE SP9]

I did a quick calculation using the longest diagonal in the room the Fq that resulted was 75Hz. This is using 8Ft. as the ceiling height.

[Doc Sage]

To take this one step further...

Does this explain why, when you hear loud music coming from a car, the bass thump always seems to be at the same frequency?

Doc Sage

[02audionoob]

what about diagonal distance? from the bottom left corner to upper right corner.

maybe there is enough distance there to let the wave travel. rooms arent 2D

And in one more direction...what about the diagonal from front bottom left to rear top right?

[JoeE SP9]

And in one more direction...what about the diagonal from front bottom left to rear top right?

See my post No. 28 in this thread.

[E-Stat]

I think it's safe to say I can hear the difference between a disorted 40Hz sound and one that is not. A 40Hz sine wave doesn't sound anymore distorted than one of 80Hz, at a reference amplitude. The cone's excursion is well within its limits when I do this. My room seems to produce a peak between approx. 40 and 45Hz which helps to extend the 686's bass. I was quite dumbfounded at first with their bass extention.
I'm largely agreeing with your assessment, but do have a couple of caveats based upon Feanor's comments:

1. As you indicated, the primary frequency of your room is around 45hz so you are getting some room gain. If the other walls are even multiples, this factor will be enhanced. My room back in Atlanta was 30x15x7.5. The fundamental frequency was just below 20 hz, reinforced by the room multiples and created a most entertaining bass effect near the back wall. The bass drum on Dead Can Dance's "Yulunga" cut shook the room. Not real, but fun! My current room is more neutral and lacks that euphonic reinforcement.

2. The primary distortion component of dynamic woofers is doubling. Which as the name suggests is second order harmonic distortion delivered at relatively high levels for small drivers at the bottom octave (up to10% or so) as compared with amplifiers. Aside: Feanor often opines that tube fanciers favor them because of this same factor. First of all, the magnitude of distortion with phono/line stages remains in the fractional percent category. Even my '81 ARC SP-6 had only 0.01%. With tube amps, not only is the peak result much lower (3%), the figure remains below 1% up to -3db output for modern pentode designs. So, back to speakers - what does that mean? Woofer distortion sounds good. Some may say better. It is consonant to the fundamental and adds "richness". Some of what you are hearing could be doubling even when the driver is within its excursion limits.

rw

[GMichael]

I seem to get very good bass from my car system. Sounds great. Very low. Very little distortion.

[yogo]

The speakers are pointed length wise


I've read somewhere on this site that in a long room you should not run your speakers lengthwise. More like this:

xxxxxxxxxxxxxxxxxxxxx
x---------O----------O----------x
x----------------------------------x
x----------------------------------x
x----------------------------------x
xxxxxxxxxxxxxxxxxxxxx

than this:

xxxxxxxxxxxxxxxxxxxxx
x---------------------------------x
x O------------------------------x
x--------------------------------- x
x O-------------------------------x
x----------------------------------x
xxxxxxxxxxxxxxxxxxxxx

Worth a shot if nothing else works. That might tame any undesirable effects between your speakers and sub. Luck...

[Auricauricle]

So it sounds like, unless you have accomodations of space to support frequencies produced by the subwoofer, your screwed!

Boy, I can imagine quite a few thousand audiophiles are getting pretty hoppy, now!

[atomicAdam]

So it sounds like, unless you have accomodations of space to support frequencies produced by the subwoofer, your screwed!

Boy, I can imagine quite a few thousand
audiophiles are getting pretty hoppy, now!

Hoppy? Sure does make you wonder.

Well, at least for me it should only be a month or two more in the small room. If Bush did anything I could thank him for the economy and housing prices are so screwed up I can affors a house.

[Auricauricle]

Yeah, "hoppy". As in quite upset, miffed, po'd, peeved, irked, irritated, annoyed, riled, fed-up, ruffled...

;)

[atomicAdam]

Yeah, "hoppy". As in quite upset, miffed, po'd, peeved, irked, irritated, annoyed, riled, fed-up, ruffled...

;)

IC - that is what I thought.

For me Hoppy = <img src="http://www.stonebrew.com/tasting/ruination/design/pfront.gif">