[cheap-Jack]

Hi.

(1) I can't tell if you're serious... a 10" sub can only go so low. There is material below the...maybe...25-29 hz you're hitting with that sub. Since you said it has 100w behind it, I'd guess not below 30 hz. It also can not reach the decibel levels many users would want.

(2) you're happy with your setup, awesome! There's better out there, but at some point, it costs more money. Do your wallet a favor and avoid hearing better.

Surely I am serious. I tested the realtime LF acoustical performance of my system in my basement audio den using a brandname audio spectrum analyser with its calibrated mic hold at my ear levels right at my sweet spot (just 15" from the backwall).

The reference music CD I used for the test is known to have electrical bass notes down to 20-35Hz & many hi-end audio studios also use the same CD to test the LF of their loudspeakers.

WITHOUT switching on the 100W 10", just testing the acoustical performance of my upgraded 2-way KEF bookshevers (mounted on a pair of leadshot-stuffed
steel tripod), I could clearly read substantial 20-40Hz signals on the screen.The entire audio spectrum was surprisingly flat with the 20-40Hz musical signal band rising up & down.

NO blind guessing, buds. 

(2) So do I NEED to wreck my wallet to add more than one sub to clean up my room acoustically? I don't think so.

c-J

[medium jim]

Getting a reading and actually having deep low reaching bass are not mutually the same.  But all that matters is if you like it, not anyone else.

Jim

[*Scotty*]

Assuming your speakers are at the other end of the room from where your measurements were taken, I would hazard to guess that you were taking your measurement at the point in the room where the standing wave at the frequency you elected to measure was at a maximum.
 If you walk forward from the rear wall towards the front wall you will no doubt measure a series of peaks and nulls at various frequencies below about 125hz and extending down to the lower frequency limit of your combination of speakers and room dimensions. If you place a sub in the rear of the room you can minimize or eliminate the peaks and nulls that exist in the room.
Scotty

[Russell Dawkins]

I can't tell if you're serious... a 10" sub can only go so low. There is material below the...maybe...25-29 hz you're hitting with that sub. Since you said it has 100w behind it, I'd guess not below 30 hz. It also can not reach the decibel levels many users would want.

cujobob, you need to get your perspective adjusted!

My first pair of Hsu subs, bought in 1993, which had 10" drivers in 36" high 12" diameter sonotubes (heavy cardboard tubes used to cast concrete columns) and long reflex ports, was 3 dB down at around 19 Hz and was only about 6-10dB down at 13 Hz. I'm relying on memory, but these numbers are close. These were being driven by a modest Adcom amp with 100 wpc. I could make my wall paneling slap noisily against the wall studs at around 15Hz - a frequency that was completely inaudible. 20Hz, in fact, was almost completely inaudible (I have a frequency generator, so I could sweep slowly across the whole audible band and then some - down to 0.5Hz.

The primary limitation of an 8 or 10 inch bass driver is output level, not low frequency limit. A pair of good 10s in reflex or sealed boxes will provide all the bass energy needed in a moderate sized room with most music at reasonable loudness levels. For open baffle, multiply cone area or displacement capability by four, roughly.

[JohnR]

The OB multiplier is a myth, so much depends on placement, EQ, effective baffle size, etc.

I guess this thread got off track. Since it already is, it would be "nice" if there were some reasonable points of agreement on how to present "bass." I feel that the decay times in the bass integration guide (which I think I linked already) are a good item for that list.

[*Scotty*]

I agree John, the room should be as non-resonant as possible below the Schroeder frequency. This reduces objectionable bass overhang and allows a more accurate reproduction of the source material.
As a rule bass bloat, overhang and boom do not occur during a live performance.
 Taking care bass resonance problems also greatly improves the home theater experience as well. Speech is more intelligible, gun fire and explosions are crisper with improved attack which greatly increases their realism.
Scotty

[medium jim]

The OB multiplier is a myth, so much depends on placement, EQ, effective baffle size, etc.

I guess this thread got off track. Since it already is, it would be "nice" if there were some reasonable points of agreement on how to present "bass." I feel that the decay times in the bass integration guide (which I think I linked already) are a good item for that list.

John, point taken....

I would also include the bloom of the note which to me is very important, then the decay....in the bloom of the note there are harmonics, overtones, half notes that are critical to the reproduction.

In defense of the thread going a bit off course, sometimes it leads to good discussions and knowledge being shared that otherwise wouldn't.   Not sure if that was the case here though.

Jim

[medium jim]

I agree John, the room should be as non-resonant as possible below the Schroeder frequency. This reduces objectionable bass overhang and allows a more accurate reproduction of the source material.
As a rule bass bloat, overhang and boom do not occur during a live performance.
 Taking care bass resonance problems also greatly improves the home theater experience as well. Speech is more intelligible, gun fire and explosions are crisper with improved attack which greatly increases their realism.
Scotty

Scotty:

Several years ago I saw Eric Clapton at the Staples Center in Los Angeles.   Had 13th row floor seats.   The opening act was Doyle Bramhall III's band (whom I know personally) and their mix was horrible, everything was muddy and boomy and I thought it was going to be just as bad for Clapton.   To my guests and my surprise Eric's sound was amazingly good.   Nathan East was his Bassist and there was no problems....same for the late Billy Preston on the Hammond B3. 

Needless to say, there were many below 40hz moments that night!

The venue is critical, but so is the guy on the mixing board. 

Jim

[rodge827]

Scotty:

Several years ago I saw Eric Clapton at the Staples Center in Los Angeles.   Has 13th row floor seats.   The opening act was Doyle Bramhall III's band (whom I know personally) and their mix was horrible, everything was muddy and boomy and I thought it was going to be just as bad for Clapton.   To my guests and my surprise Eric's sound was amazingly good.   Nathan East was his Bassist and there was no problems....same for the late Billy Preston on the Hammond B3. 

Needless to say, there were many below 40hz moments that night!

The venue is critical, but so is the guy on the mixing board. 

Jim

Jim,
Not trying to get off topic, but my experience at live events is the same as yours. My belief is that opening acts don't get the same "respect" as headliners do with the sound system. What you wrote can be said for 99% of all the live concerts that I've been to. It's a shame but I gues the headliner can't be upstaged?

Chris

[Russell Dawkins]

The OB multiplier is a myth, so much depends on placement, EQ, effective baffle size, etc.

Are you saying that the fact of reduced output (for a given placement, amp power and so on) is a myth or that 4 is too large a factor?

By open baffle, I was imagining the common very narrow baffle or smallish H-baffle as is commonly employed in most of the OB designs I have seen.

[cheap-Jack]

Hi.

(1) Assuming your speakers are at the other end of the room

(2) from where your measurements were taken, I would hazard to guess that you were taking your measurement at the point in the room where the standing wave at the frequency you elected to measure was at a maximum.

(3) If you walk forward from the rear wall towards the front wall you will no doubt measure a series of peaks and nulls at various frequencies below about 125hz and extending down to the lower frequency limit of your combination of speakers and room dimensions. If you place a sub in the rear of the room you can minimize or eliminate the peaks and nulls that exist in the room.
Scotty

(1) Yes, my loudspeakers are seated the other end of the room (long side of the room), each about 6ft from the front wall.

(2) No, I only measured the louspeakers from WHERE I always sit per the instruction given with the audio spectrum analyser. I think that only makes sense as anywhere else does not reflect the actual sound wave pattern arriving my ears.

Any bass resonances inside the room should be already taken toll on where I sit, correct???

Now my ears can't detect any bass problems, which was verified by the reading on the spectrum analyser.

So why should I still bother???

That's why I challenge the validity of the CABS white paper as per my situation.

Frankly how often do we play subsonic bass music that demands multi subs to clean up the bass resonances? FYI, I don't switch on my sub unless I play pipe organ music as my stereo loudspeakers already get adequate LF response to handle most music I play. I am not that sub-bass obcessed.

c-J

[James Romeyn]

Except for a couple of live mixes a few years ago (beyond awful, I could not hear the mix during the show) the last live mixing I did was in the 70s (19, not 18) for a medium sized church.

Human flesh being mostly gelatinous, it is almost 100% absorptive.  Have a friend stand in front of either the L or R speaker to test this.  Depending on size of the speaker and the blocking body, output at the sweet spot might equal disconnecting that speaker.  Ever noticed how much power your system looses with a lot of people in the room?  Gelatin in the house!   

What may be the first and second best bands in concert I've seen (doesn't include  being in the studio with Roy Buchanan and Tower of Power) were, in this order, Sting in Denver and Paul Simon in Las Vegas.  It was fun in the 3rd row in Vegas yelling, "Happy Birthday" to Paul and getting a little salute.   

Anyway, when Sting appeared with his band (including a father and son duo) and started playing I was, um, not happy having almost died on the ice in Montana because the sound was pretty horrific. 

It quickly improved to mesmerizing great live sound.  Believe, me it wasn't like I just got used to the bad sound, because I'm reliably repulsed by same and increasingly want nothing to do but leave.  The crowd including me was hypnotized during a 6-8 minute song wherein the violinist played a 2-3 minute solo like a banshee.  Electricity in the air. 

How can a sound person tune it correctly minus 3-5k large gelatinous creatures in the audience?  I imagine they get it as close as possible with no audience, then start tuning like a mad dog as soon as the band appears and starts playing with the audience seated.  Is there a computer program that accounts for audience bodies?  It's not like they could play pink noise or "pings" at various frequencies with the audience present.  "Excuse me, would you all please tightly plug your ears for about 60 seconds?  Thank you."   

[medium jim]

Guys, let's try to get this back on subject.

Jim

[doug s.]

...I have always felt that bass is the bones; midrange, the flesh; and treble, the skin of music.  Without good bone structure, you just can't get good looks...   ...I can't stand boomy bass but I can't stand lack of bass either.      

So for me, I need to go below 40hz every time I turn my system on,

+1!

when i first went to outboard subwoofers, actively crossed over to my main speakers, my mains were rated -2db at 19hz.  the improvement in bass by having dedicated subwoofers was not subtle.  and the main speakers sounded better as well, w/them and their amps now being relieved of seeing anything below ~80hz...  and, everything seems to sound better, not yust orchestral music or electronic synthesized low frequency bass.  even a great acoustic jass/bluegrass album like jerry douglas'/russ barenburg's/edgar meyers' "skip hop & wobble" sounds better...

some day, when i have the space and the wherewithal, i will have a pair of subs set up behind the listening area, wired out of phase w/the front subs...  i think this would work great, even in a smaller room; the subs simply do not have to be as large...

ymmv,

doug s.

[*Scotty*]

See my reply to cheep-jacks post (No.70) in this thread, "One vs Multiple Subs and why?"
http://www.audiocircle.com/index.php?topic=106756.msg1098641#new
Scotty

[JohnR]

Are you saying that the fact of reduced output (for a given placement, amp power and so on) is a myth or that 4 is too large a factor?

Compare the blue and purple curves below. By moving the dipole panel, there's over 12 dB more output in the 20-40 Hz area (keeping somewhat on topic for the thread ). So there's a factor of four in number of drivers, just by moving the panel.