interesting topic
and lots of good poits mentioned already
simple unswer to above question is: there is never enough!
let me explain, I do not mean to have system overly bassy, no no, there has to be just the right amount of bass, I like whole fr response in my listening position as flat as possible. Therefore I do use 31 band equalizer
most often its not how much bass is there, its mostly how extended and free of peaks the low fr spectra is
small speakers obviously have tendency to roll off too soon and people compensate with loudness button or bass/treble settings
-but these are too coarse to flatten the response, they just create big bump in the upper bass, which is nasty
if you follow the line of many manufacturers, from smaller bookshelf to biggest florstanders, sound improves with improving the bass, that is obvious, we all know that
quite often the same tweeters and midranges are used, but how the bass is executed makes or breaks the fidelity
hence my unswer...improving the bass gets speaker into higher level
some people might be happy with less, but not me
some people like the sound of fullrange speakers, me too, but not without subwoofer
it all comes to personal preference
I go to live concerts often, mainly because I live in DC area, where there is lots of opportunities, either live jazz in bars, but mostly classical in Strathmore concert hall, the new hall next to me...now every time I go and enjoy the music, I rush home and compare, well, I have been working on my systems for years and I am mostly happy, but its always the bass which lucks in comparison to real thing
few weeks back I went to Orff's Carmina Burana, boy, that's sheer madness, it's composed to sweep you of your feet, it takes your breath away...I listened to it dozens of time at home, but the dynamics and loudness in live performance is phenomenal
so in short, while my systems sounds great at home for low sound levels, they are not enought in bass mostly in fortisimos
I do use lots of woofers, my open baffle fullrange is accompanied with 15" woofers, my line array is accompanied by 2x 15" woofers per side, and my horn system uses one 18" woofer, so all in all I did not make shortcuts there, maybe I need more power in amps powering the woofers (I use solid state exclusively here, while tubes exclusively for midrange and hights), in conclusion, its never enought
while I do not listen too loud, only when occasion calls for it
so it's fine at normal level, but I want the real thing!
not to mention that I like requiems and masses so I go to church concerts too...and to reproduce berlioz's requiem or grand mass with all the big pipes of organ and all those tympany is not an easy thing
I am almost done, so bear with me, one more thing
I do sound for amateur music group at my work place
they are good musicians, they all playing somewhere else, just got together to entertain for company getherings
I have no problem to make them sound good and plenty loud in small conference room or cafeteria or so
however, we once played on Pennsylvanie Ave for some benefitiary concert
well, I did what I could, but we just run out of bass
I sweezed max of amps and speakers, but low bass is hard to achieve in completely open space
as they are amateurs, they do not have much gear, the main spekaers I built for them have four 18" woofers (I think 400w each) and we blew a couple of them
so in conclusion when it comes to bass, there should be just enough bass to have flat and well extended fr response, it should have plenty spare power to response well to peaks to keep up with dynamics, it should be free of nasty room resonances, and it should sound natural, just like live music
ed
www.volvotreter.de -> Tapped Horn and look at the big Eminence version. A 3015LF will work in it and is <$A300 driver airmail from the US. These are large but have a small footprint (look at Erik's pics) but no worse than the suggested El-Pipo. Simple to build and a huge amount of output to 20Hz.BHTX said:
You have a lot of good points here. I never did get around to building the electronics, I just use an outlaw ICBM with the lowpass set at 30hz. I think you need the gain from Rod's circuit due to the low efficiency of a single driver.
I built a passive notch filter to remove some output at the resonant frequency of 80hz. In theory, you would expect flat response from roughly 30 to 80 Hz, with the output dropping off at 12dB/octave above 80 Hz. That's pretty much what it measures out to.
The multiple drivers get the efficiency up to a reasonable (for a subwoofer) level. If I recall correctly, it calculates out to 84dB at 20 Hz. (Eff drops off at 12dB per octave below resonance in a sealed box.) The multiple drivers also reduce the cone excursion needed. If they are doing +-2mm, the windows are rattling.
My previous sub was a TL using two 10" car audio subwoofers. It was rather resonant, with a big peak at 50Hz. Enjoyable, fun, but not very articulate.
JJ
Steep 60Hz LPF would be OK I reckon.cowanaudio said:
They're still smaller than the El-Pipo. Maybe something like this would be better for most domestic applications.
http://www.teresaudio.com/haven/subs/subs.html
I'm contemplating some of Erik's design later as I have a few 3015LF's here unused. My earlier idea for the LAB12 version has been canned as the LAB12's are currently in an experimental push/pull manifold (front) sealed (rear), similar I believe to your Peerless under your Unity's that we spoke about before. The sims go to 40hz half space, and will likely do better in the current room. When I get the big room back, some of Erik's (or similar) will do 20-50 or so, under the LAB manifolds.
I am considering this 18" FANE with neo motor ... seems good fore a closed box ... Fs=34hz with only 122gr mms seems ok fore home use ... obviously no double spider
http://www.fane-acoustics.com/pdfs/Colossus18B600N_SpecSheet.pdf
http://www.fane-acoustics.com/pdfs/Colossus18B600N_SpecSheet.pdf
You seem to be getting efficiency and response and output mixed up/interchanged.jupiterjune said:
Using single or multiple drivers has nothing to do with efficiency.
Similarly, a tapped horn's response does not change with multiple drivers.
Yes, multiple drivers will reduce cone excursion for a particular output level or allow a higher output level from a set of drivers.
Brett said:
G'day Brett
As I said that will require a fairly stout mid bass section to keep up. My preference would be to go sealed, and to get good efficiency and output at this crossover frequency a pair of Pro 12" drivers or a 15" would probably be required. I used to run an 18 Sound 15LW1401 from 70 to 300Hz under my horns, and that was the lowest efficiency and lowest output section of my system, at 70Hz I had around 90dB/W/1M. That driver is pretty serious compared to the standard fair in the hifi world.
Cheers
William Cowan
Well, possibly I do not use efficiency and sensitivity correctly, as one usually refers to dB 1W/m, and the other dB 2.83V/m. Frankly, I can never remember which is which.
My post was in regards to Rod Elliot's ELF subwoofer, but built with multiple drivers, in this case 8 in series parallel. Your efficiency truly does increase with multple drivers wired series parallel.
The comment about the gain I made might be a bit confusing. I believe Rod's circuit gives increasing gain from your resonance point (say, 80Hz) down. This gain is necessary if you build the ELF with just one driver. Your sensitivity might be around 60dB 2.83V/1m at 20Hz. A low pass crossover "set" for 20Hz (which would actually be -3db at 20 Hz) starts attenuating at just above 20Hz as you go up. So, if your sensitivity was 60 db @2.83V/1M, it would remain flat up to the resonanance point of the speaker. You would need a 24 to 30dB of gain or so to match the level of the sub to your main channels.
JJ
JJ
Hi William,cowanaudio said:
I agree 100% it'll take a serious midbass too keep up with the TH's max capabilities, or a more modest one with the TH merely idling.
I only use Pro drivers nowadays so I forget about the little 'phile ones and their (lack of) capability. 15" drivers are midbasses to my eye and I'd also go sealed as a general preference.
I'll also soon have some Yorkville U15's to play with.
Hi,
the efficiency of the driver/speaker does not change when multiple drivers are used.
The sensitivity of drivers used in multiple arrays does change over a small frequency range.
Each doubling of drivers achieves a theoretical 3db increase in sensitivity. 1driver =XdB/m/W, 2drivers =X+3 dB/m/W, 4drivers =X+6dB/m/W, etc for larger arrays.
It does not matter whether 1W is used as the base reference or if 2.83Vac is reference.
It is very obvious that the last few posters have completely misunderstood the difference between driver sensitivity and driver efficiency, usually quoted as n0 (the Greek lower case Eta) in percentage terms in the datasheet.
MJL,
you did not reply to my Email?
the efficiency of the driver/speaker does not change when multiple drivers are used.
The sensitivity of drivers used in multiple arrays does change over a small frequency range.
Each doubling of drivers achieves a theoretical 3db increase in sensitivity. 1driver =XdB/m/W, 2drivers =X+3 dB/m/W, 4drivers =X+6dB/m/W, etc for larger arrays.
It does not matter whether 1W is used as the base reference or if 2.83Vac is reference.
It is very obvious that the last few posters have completely misunderstood the difference between driver sensitivity and driver efficiency, usually quoted as n0 (the Greek lower case Eta) in percentage terms in the datasheet.
MJL,
you did not reply to my Email?
Great thread.
I see two rather important points here:
So true! Real acoustic instruments are very loud, or at least can be. In a big space, that's OK - but I find it overwhelming in a small room. Yes sometimes I want to "rock out" or "symphony out". But most of the time it need not be nearly that loud to enjoy and convey the emotion. ~80dB average is fine for me. My neighbors thank me for it, too
Right. But I'd reduce that by about 10dB in two ways.
First: Most classical CDs I've seen are mastered with an average level of -22dB or -20dB below full scale. That means peaks can be no more than 22dB above average.
But that's still way more dynamic than most other music.
Second: As stated above, an average of 90dB in the lounge is damn loud. Maybe in a nice dedicated listening room it would sound great. But not in my living room. About 80 is all I want. So that puts peaks at only 100dB for most listening. And a lot of those musical peaks are in the 500-1000Hz range.
What I've found in my living room is that a good, solid, clean bass makes even the "lower than real life level" stuff sound very satisfying. So it doesn't have to be super loud to sound big and bold. If you know what I mean.
Just my 2 cents.
I see two rather important points here:
So true! Real acoustic instruments are very loud, or at least can be. In a big space, that's OK - but I find it overwhelming in a small room. Yes sometimes I want to "rock out" or "symphony out". But most of the time it need not be nearly that loud to enjoy and convey the emotion. ~80dB average is fine for me. My neighbors thank me for it, too
GM said:
Right. But I'd reduce that by about 10dB in two ways.
First: Most classical CDs I've seen are mastered with an average level of -22dB or -20dB below full scale. That means peaks can be no more than 22dB above average.
But that's still way more dynamic than most other music.
Second: As stated above, an average of 90dB in the lounge is damn loud. Maybe in a nice dedicated listening room it would sound great. But not in my living room. About 80 is all I want. So that puts peaks at only 100dB for most listening. And a lot of those musical peaks are in the 500-1000Hz range.
What I've found in my living room is that a good, solid, clean bass makes even the "lower than real life level" stuff sound very satisfying. So it doesn't have to be super loud to sound big and bold. If you know what I mean.
Just my 2 cents.
Hi Pano,
thanks for reminding us again that sensible average and transient peaks are the critical levels for reproduction.
I heard a school "African drumming" band at a venue recently.
My closing remarks to the group I was leaving with:
"if only I could get my sound system to reproduce that at home".
The "leader" was blowing a whistle throughout the performance. It could only be heard during the pauses, not even during the quieter passages.
BTW,
that 90dB +30dB of overhead comes to 120dB. Geddes recommends a target of 130dB for transient peaks in his listening room.
I try to aim for 110dB of transient peaks (90+20 for "loud" if that's what the mood requires), but my systems cannot get there yet.
thanks for reminding us again that sensible average and transient peaks are the critical levels for reproduction.
I heard a school "African drumming" band at a venue recently.
My closing remarks to the group I was leaving with:
"if only I could get my sound system to reproduce that at home".
The "leader" was blowing a whistle throughout the performance. It could only be heard during the pauses, not even during the quieter passages.
BTW,
that 90dB +30dB of overhead comes to 120dB. Geddes recommends a target of 130dB for transient peaks in his listening room.
I try to aim for 110dB of transient peaks (90+20 for "loud" if that's what the mood requires), but my systems cannot get there yet.
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