Ambience, a feeling of the venue
I love physics. Sir Isaac Newton is in my top of the list-of-favorites. You know, if there was as much attention paid to what it takes to get bass-time smear
reduced, or eliminated, the open baffle cult would have never been borne.
Obviously (or maybe not?) a hint to what it takes to reproduce the feeling of the acoustic hall. I certainly do enjoy mine. 🙂
I love physics. Sir Isaac Newton is in my top of the list-of-favorites. You know, if there was as much attention paid to what it takes to get bass-time smear
reduced, or eliminated, the open baffle cult would have never been borne.
Obviously (or maybe not?) a hint to what it takes to reproduce the feeling of the acoustic hall. I certainly do enjoy mine. 🙂
Well, as explained: i'm actually using 4x 10W7 in sealed boxes with massive EQ boost in the first half of the 1st octave...
Non-EQd single 10W7 would probably be enough for most people i know... So for my specific needs, it's a waste of time to even consider OB for the lower-end.
But, yes. It's probably possible to get ''decent'' first octave with OB. Like it's possible to reach 140mph in a Toyota Camry. I'd still prefer doing that in a Porsche.
🙂
Yes i did, even though it was few years ago...
But my question about the Qts was more about the drivers usually available on the market, rather than what is theoratically possible/optimum.
I already know that guys who love digging the vintage stuff and/or exotic stuff will more likely end with unusually low or high Qts drivers, while many of the modern stuff is contained between 0.3 and 0.5 (correct me if i'm wrong, i might be biaised)
Most of the people would be content with a F3 35hz even if they have passive rads that brickwalls anything lower...
And some HT people will only be happy if they get 12hz in-room flat pressurisation.
By experience, i think having something solid from 23-25hz is worthy. Either in-room/listening position flat, or with a boost from that point up to roughly 30-33hz and up to 5-8db. In fact that's the only place where i ''cheat'' my frequency response to unflatten it. Never heard any complaint about it, but i did stumble upon few Sci-Fi movies that makes it a bit too much! But for music, not at all, even the most extreme electronica.
Not sure, though, if having something flat/boosted from 23hz and downward is worthy. Even for HT.
You must be listening to some wimpy open baffles. They are unfortunately common. If someone wants to build a no baffle speaker, then yes, they'll be wimpy. Doing OB with 10" drivers will also sound wimpy. Big music won't sound real on those.
I've worked with open baffle speakers that played down to 16Hz, so what?
People are always getting hung up on numbers. So hung up in numbers that they forget audio. Sorry, I just don't believe a lot of people understand what bass is. It isn't just a number. The numbers game is just bragging and boasting, as tho that's what makes bass. There is so much more to bass than some claim of a low number. Puts me in mind of a guy who walk into an audio store and says "How many Watts does them speakers do?"
Yes, I've heard a lot of anemic OB speakers, but that's because most people don't understand how to build them. I've built a few like that myself. I've also heard plenty of box speakers that claimed fantastic bass down to some low frequency they couldn't reach. I just smile, nod my head and say "Sure, sounds great."
Perhaps it's a new spin on "This one goes to 11". 😉
I stacked 15dB of parameteric EQ with the Behringer DEQ2496s auto-EQ which landed on another 12dB of boost around 25Hz.
The drivers were good and the amplifiers powerful, so I had headroom to play with. That said, the mid and high-range were just idling along (10" mids and compression driver HF) when the woofers were seeing real power.
Low Qts means the driver won't add much output around Fs. High Qts drivers (Eminence Alpha 15, I'm looking at you) will add lots of output around Fs. In the case of the latter, that's enough to get a reasonable low-frequency response just by slapping a driver on a baffle. Low-Qts drivers will need boost, and a lot of it. Excursion requirements are the same, though, for a given baffle size.
Chris
Well they were 60 cm wide and had two 15 inch woofers per side; that's what just fits in my listening room which is my personal room so no WAF to cope with 🙂.
Like said before when music genre fits they are great, but they are simply not able to pressurize the room and provide the impact as experienced in the concert hall.
I am curious how your 16 Hz OB's looked like; could you give us some more info 🙄?
The best bass I ever heard were produced by transmission line loudspeakers; with some imagination they are comparable with 10 feet wide OB's.
I use four 10" Vifa woofers per speaker and need 20 dB to get 40 Hz flat, and still have usable output to around 30 Hz.
I use digital eq so I don't boost, but pull down instead. You just need to have enough output from your preamp to feed the amplifiers, then it's no problem.
At the moment it's powered by a Panasonic SA-XR55, but will be replaced by MDA400 monoblock (I am puttig them in another case at the moment). Even with 20 dB and a Panasonic SA-XR55 I can play plenty loud. And I might even have too much bottom end.
I have a very nasty room resonance at 50 Hz, and I have tried all sorts of boxes and eq, but the best in my room is OB.
If I could I would use a closed box.
Well that should do it. Two 15s per side, a wide enough baffle. Don't know why it wasn't working for you. That should not be wimpy.
I don't understand what you mean by this. What type of concert hall? Sympathy hall? I've attended and worked plenty of symphonic concerts, and can't remember ever having the sensation of a pressurized room. My ears just doesn't hear that in a huge room with acoustic instruments.
Now if you are talking rock concert, then yes of course. That's a result of many 100s of watts pushed into dozens of high efficiency loudspeakers. It can rattle your insides. I know a lot of people pay good money for that effect because it's so much fun, but it's an electric effect, an amplified, manipulated sound, not one of acoustic instruments. That punchy bass is done with electric manipulation.
2x18" woofers, a 10" mid + tweeter per side, IIRC. They were at LSAF in 2010. Baffle about 60cm wide. But it wasn't their ability to play down to 16HZ, or 22Hz, or 32 Hz that made them so satisfying in the bass. It was there ability to move a lot of air, cleanly and with great authority throughout the bass range. Most listeners looked a bit shell-shocked after hearing them. No one went away asking for more bass. But they aren't unique. I've heard it done with other twin 18s, 18+15 and some twin 15s.
In my lava cave listening room I had semi-open baffle speakers that measured down into the 20s. Clean, pure bass with no ring or overhang, but also no punch, no weight. A single 12 per side in a big space just won't cut it.
I'm not an OB fanatic, I also like sealed and ported boxes. The "best bass" I've ever heard came from a large box with silly little ports, the Onken W.
But when I hear or read people talking about how OB does not have good bass, I just SMH. OB can have very satisfying bass, if it's done right. Too often it's not.
Let me (try to) explain.
Yes, in this case I mean a concert hall with a symphony orchestra.
I "feel" the sensation of a big drum which does not have to be played fortissimo to get "heard", especially when amplifying a bass line played by the orchestra.
Note that I say "feel", not "hear". The attack of the drum can clearly be heard, but there is additional "pressure" which is "felt" rather than "heard".
A similar case is a big organ played in a big church or cathedral.
The low pitched pedal tones of the organ are not only heard but also felt.
In my experience OB's fall short in reproducing that very lowest octave because they are not able to pressurize a room; that is just physics. Above let's say 60 Hz up to some 200 Hz, still what we call the bass range, OB's can play well enough (with all their inherent advantages).
OB bass
Pieter....
Your disappointing OB bass experience is not all that uncommon. But, if designed correctly, an OB can do exactly what you describe. And do it better than most box designs.
I attend Symphony orchestra regularly. Fortunate my small town has a full time 80 member group with a 6 concert winter series. That includes full percussion, 6-8 each 3/4 and or full stand up bass depending on the piece being played and all the rest. Attended last week. Just love it! Modern 850 seat hall. Concert master and director go all the way back to working with Bernstein in NY! What a gift!
To get the bass drum correct (60" tuned in the low 30's or below)... so that you feel it as much or more than hear it, a speaker must be able to move a lot of air at the bass drum fundamental, while keeping the harmonics at their proper descending levels. Depending on room size and baffle path difference, you can do this with a pair of 12" woofers on each baffle at moderate playback volumes. Dual 15 inch is better, and a couple of 18" really gets it done. I have even done dual 21"! You can do it passively or actively.
But there is more.... you also have to keep the correct harmonic structure and flat in room response through the complete audio spectrum. This is not easy, but when you do it you do experience the visceral aspect you describe.
It's all about engineering!
Pieter....
Your disappointing OB bass experience is not all that uncommon. But, if designed correctly, an OB can do exactly what you describe. And do it better than most box designs.
I attend Symphony orchestra regularly. Fortunate my small town has a full time 80 member group with a 6 concert winter series. That includes full percussion, 6-8 each 3/4 and or full stand up bass depending on the piece being played and all the rest. Attended last week. Just love it! Modern 850 seat hall. Concert master and director go all the way back to working with Bernstein in NY! What a gift!
To get the bass drum correct (60" tuned in the low 30's or below)... so that you feel it as much or more than hear it, a speaker must be able to move a lot of air at the bass drum fundamental, while keeping the harmonics at their proper descending levels. Depending on room size and baffle path difference, you can do this with a pair of 12" woofers on each baffle at moderate playback volumes. Dual 15 inch is better, and a couple of 18" really gets it done. I have even done dual 21"! You can do it passively or actively.
But there is more.... you also have to keep the correct harmonic structure and flat in room response through the complete audio spectrum. This is not easy, but when you do it you do experience the visceral aspect you describe.
It's all about engineering!
First Octave OB
By first octave, I assume you are inferring 20-40 Hz. 30-60 Hz is the first octave for the majority of OB's I am familiar with. You can get an OB to play flat to 20 Hz, but it's going to be pretty large or VERY inefficient!
The big thing for me is the freedom from stored energy and the resulting maintenance of correct pitch and harmonic structure. This also assumes the OB is correctly designed. You don't realize how much a box alters bass until you hear a good OB next to it. It is not all that unusual for the surfaces of a well built box to radiate as much or more than the driver cone. And you have internal box reflection re-radiating into space through the cone. And out of phase to boot!
By first octave, I assume you are inferring 20-40 Hz. 30-60 Hz is the first octave for the majority of OB's I am familiar with. You can get an OB to play flat to 20 Hz, but it's going to be pretty large or VERY inefficient!
The big thing for me is the freedom from stored energy and the resulting maintenance of correct pitch and harmonic structure. This also assumes the OB is correctly designed. You don't realize how much a box alters bass until you hear a good OB next to it. It is not all that unusual for the surfaces of a well built box to radiate as much or more than the driver cone. And you have internal box reflection re-radiating into space through the cone. And out of phase to boot!
This is not entirely true. The difference between OB bass and boxed bass, is that the box reproduces the fundamental whereas an OB only reproduces harmonics without the fundamental. This appears to the ear as "better bass", or "quick and fast bass". This distortion is known as "doubling". In a very well designed and built "box" there exists the possibility that no additional radiation occurs. You just have to know how to do it.
Attachments
BuT a very huge room do we really need a so low 20 Hz F3(measured in anechoic chamber) ?
We have more chance to have a boomy sound in most of the rooms ! 30 or 35 Hz is often enough imho, nicer to listen to with a targett curve close to the ISO 2669x.
We have more chance to have a boomy sound in most of the rooms ! 30 or 35 Hz is often enough imho, nicer to listen to with a targett curve close to the ISO 2669x.
Hello again Scott....
I find your position that an OB does not produce fundamentals? If any reproduction system is prone to doubling, it's boxes, especially ported.
And if the OB is not producing fundamental wave forms, is there a frequency where they can? I am puzzled by your logic too. Hmmm.....
I find your position that an OB does not produce fundamentals? If any reproduction system is prone to doubling, it's boxes, especially ported.
And if the OB is not producing fundamental wave forms, is there a frequency where they can? I am puzzled by your logic too. Hmmm.....
Agree with that for the bandwidth an OB can reproduce well, let's say from 60 Hz up; I agree with Jon that it does not seem necessary to squeeze out that lowest octave with an OB, and I am not convinced that an OB, able to reproduce that lowest octave, would sound better than a well designed subwoofer.
In a well designed sub, surface and through cone radiation is not an issue. Our ears are much more sensitive to this at mid frequencies where wave lengths of sound more or less cope with box dimensions.
My take is to let OB's reproduce what they can do well, and fill in the lowest octave with a dedicated (room corrected) subwoofer like for example Gedlee's multi-subwoofer approach.
OK ... some anecdotal evidence on deep bass production abilities of a large OB.
I test every OB I build. Part of that is a frequency sweep appropriate for the particular design. Mainly listening for rattles, voids in response, speaker lead slap and the like. On my dual 15", dual 18" and dual 21" I take them all the way down to 20 Hz where the cones have little or no loading. So it only takes a few watts to drive them to there mechanical limits.
What is fun about it is learning where the system cuts off acoustically. I can go outside the building and feel the ground moving at 32 Hz with the dual 18 and 21 models. Harmonics will not do that! Pipe organ stops and all the rest are there too and the ARTA & Holm system evaluation tools record those deep bass fundamental as there. You can see the fundamentals displayed very nicely on the computer screen. I have an old AR-3A that I use from time to time as a reference. On the same screen using the same mike at the same distance with the AR-3A a couple of inches out from the wall 20" off the floor it is about 4 db down at 32 Hz. And you can feel it being down a bit too. BTW, the 12 woofer in the AR-3A playing at its peak Xmax (8mm peak) only delivers about 94 db or so at 1 Meter at 32 Hz. The dual 21" kick out 106 db and it's way cleaner!!
The point is, given enough horse power, a barn door will fly!! Oh yeah, they built that... F4 Phantom I think it was called!!
I test every OB I build. Part of that is a frequency sweep appropriate for the particular design. Mainly listening for rattles, voids in response, speaker lead slap and the like. On my dual 15", dual 18" and dual 21" I take them all the way down to 20 Hz where the cones have little or no loading. So it only takes a few watts to drive them to there mechanical limits.
What is fun about it is learning where the system cuts off acoustically. I can go outside the building and feel the ground moving at 32 Hz with the dual 18 and 21 models. Harmonics will not do that! Pipe organ stops and all the rest are there too and the ARTA & Holm system evaluation tools record those deep bass fundamental as there. You can see the fundamentals displayed very nicely on the computer screen. I have an old AR-3A that I use from time to time as a reference. On the same screen using the same mike at the same distance with the AR-3A a couple of inches out from the wall 20" off the floor it is about 4 db down at 32 Hz. And you can feel it being down a bit too. BTW, the 12 woofer in the AR-3A playing at its peak Xmax (8mm peak) only delivers about 94 db or so at 1 Meter at 32 Hz. The dual 21" kick out 106 db and it's way cleaner!!
The point is, given enough horse power, a barn door will fly!! Oh yeah, they built that... F4 Phantom I think it was called!!
As John says, where do you think the frequencies on the measurement pots come from? Surely the measurement software isn't confusing the harmonics for the fundamental.
Yes, we've all heard our fair share of OB that have no real bass. Too many of them get built like that, then rave about the "clean bass". Once you hear an OB that really does reach low, you'll know it and it's impressive.
Yes, we've all heard our fair share of OB that have no real bass. Too many of them get built like that, then rave about the "clean bass". Once you hear an OB that really does reach low, you'll know it and it's impressive.
Agreed for the 80hz-500hz or so, and maybe even from 50-60hz, but i really don't see how any audible benefits could results in OB v.s. sealed box for the first octave.
Not to mention the extreme difficulties to achieve any decent 20-30hz in OB...
Anyway, that quite easy to test and compare, isnt it ? Let's say i put a 18FH500 on a 4'x8' wood panel, can i expect to have everything for a fair comparison with my ''real'' subwoofers ?