Me too, I am immensely happy looking at my 2 x 18", and when they also radiate the sub-frequency content of the music, "I touch the sky with my hands" !
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Big subs vs Small subs
- Thread starter ex audiophile
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I am afraid your opinion does not change definition of a pulse. Even Wikipedia explains pulse as a rapid, transient change in the amplitude of a signal from a baseline value to a higher or lower value, followed by a rapid return to the baseline value. What REW generates is a sinewave with an envelope of a pulse. It is not a pulse. It is a shaped sinewave.
Really ?? It's just all about being definitely correct?
And no, REW doesn't generate shaped sinewaves as bursts, other than for CEA. Look at the one cycle REW screen i posted.
Like I said... if the cycle bursts don't meet your criteria, generate a Dirac pulse. Which defintely meets wiki's def.
But then you'll find you get very little info from the sub...because the pulse has very little low freq content, provides very little stimulation without boatloads of amp gain, and doesn't allow assessing how a sub loses linearity across frequencies.
Or heck, use REW's generator to produce a 1/2 cycle pulse...which also meets wiki's def.
Indeed, let’s!
Do please look at the label above the 50.0 in big letters, it says Frequency and check the selected tab’s name: tone burst. A tone is a synonym of sine wave.
That single cycle is the envelope of the 50Hz sine wave.
I understood something else, that large speakers with poor technological development can give distortions due to mishandling of the cone, which is true. But it would have to be really bad, a big name brand speaker will outperform a small "ultra-developed engine and suspension" speaker for much less money.
In reality, just like current tower technologies with many smaller speakers that can be well outperformed by a single, well-built larger driver, the limiting factor is size, more precisely "footprint". In a world sparse of large houses and with more and more apartments, technology adapts to sell its products to those "niches". Which are the vast majority, why do you think JBL began to venture into small self-powered speakers?
The SVS statement is correct, then they go through a lot of technical justifications to convince that determined public and who is eager to hear what they proclaim... a small subwoofer can give the same or better acoustic results than a large one. ...!
Yes, it can, but not always. Depends on so many things... :
" Low frequency extension and sound pressure level (SPL) are widely considered the two most important factors of a subwoofer’s performance. The laws of physics dictate that a massive subwoofer driver has the potential to produce greater SPL and deeper bass than a smaller subwoofer driver. The ability to shake our pantlegs, pound our chest, and make it feel like the room is breathing with greater intensity, these are the strengths of a properly engineered big subwoofer driver.
SPL and low frequency extension aren’t the only important measures of performance, however, and not all big drivers perform with equal aplomb. Accuracy, speed in transients and the ability to blend seamlessly with full range speakers are also critical factors when judging the performance of any sized subwoofer, and a subwoofer driver is only as good as the motor and amplifier backing it up so a bigger driver doesn’t always mean better performance. "
You can be sure that this cone will not stray away from pistonic movement and its larger SD will need less Xmax to achieve the same SPL as that SVS speaker.
Eighteen Sound - Professional loudspeakers
A very good woofer but not suitable for a subwoofer, not even with a DSP.You can be sure that this cone will not stray away from pistonic movement and its larger SD will need less Xmax to achieve the same SPL as that SVS speaker.
Eighteen Sound - Professional loudspeakers
www.eighteensound.it
sarumbear, i'm not going to debate weedy definitions with you.....I leave that to the academic types...
If you want to discuss something more meaningful, like how actually measure transient response of subs, like I presented with using tone bursts, I'm wide open for corrections and suggestions.
But ignoring the big picture goal and debating technical definitions, instead of working together to form better common understandings,
is a fools game imo...so pls count me out.
I have not heard all my own designs properly, so travelling aroind the world to hear someone else's creation is not exactly top priority.
I’m disappointed that you call physical definitions as “weedy” and you think that only the “academic types” should use them. It’s obvious to me that you have never had any basic engineering education like physics and math but trying to be one.
Indeed it is…count me out too. I can only discuss technical matters with people who understands them.
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I’m sorry I phrased my question badly, I apologise. I meant to say have you heard of them, about their RTL design, which also use a wide bandwidth port.
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Here different bass-system configurations going from 1 to 2 to 4 subwoofer units were tested and measured. There was no huge difference in tactile feel going from 1 to 4x, which is similar to small sub and very huge sub. If there was a noticeable difference, it would be mentioned here (article is in norwegian langue, use translate, or simply ignore and just look at the graphs):
https://www.kvalsvoll.com/blog/2018/03/10/4x-2x-1x-subwoofere-hva-er-forskjellen/
https://www.kvalsvoll.com/blog/2018/03/10/4x-2x-1x-subwoofere-hva-er-forskjellen/
Well, i ran through every math and science class offered in high school, and was given a grant to do independent physics study my senior year.
When I got around to going to college, I was set on business, so a math minor was all the science & math I could squeeze, given getting majors in economics and finance. Grad school was world class, but not much math other than statistics. Employment had me working as a peer with accomplished profs and academics, including Nobels, lured away from universities..
So i know how to talk the "definitional talk" when needed....which I've found is surprisingly needed less often, once out of school.
In fact, the more accomplished the level of academic I encountered, the less they relied on strict definitions, unless the definitions were needed to differentiate focus-worthy points or alternatives in a discussion.
It's a huge mistake imo, to strictly require science discussions hold to bunch of definitions, and how they relate to each other. (note i said strictly)
And for a Professor, it's a huge mistake to make that definitional method what is taught. Those guys bored me to death; and worse, all I learned was how to parrot out stuff for the next exam.
Now take Professors like Feynman, who I would love to have been able to sit in class with, ..... profs that I had, that were more like him, imparted real understanding. They were utterly fascinating and full of real teaching ability.
And often kept the instruction within a grade school vocabulary, to help impart understanding..
Anyway, all the above said in the interest of peace......
So my bottom line: if the definitional distinctions differentiate focus-worth points or alternatives in a discussion, they fit well imo.
If not, why utter them?
I'm making progress on fixing my room. I thought that I'd try putting my Martin Logan Dynamo 1100x sub on an extra stand that I had. I can have it down firing or front, I prefer front. I sit 8' from each speaker and 7' from the sub. "I think" it creates a literally "in your face" experience... when the kick drum is explosive and pushing a lot more air higher, because of the elevated stand. This is also an attempt to decouple from the floor. Nuts? Thoughts? Please expound.
Note: in the pic, it looks like the sub and amp are on the same rack, they are not.
Note: in the pic, it looks like the sub and amp are on the same rack, they are not.
I posted that link as an example of a great big speaker build, to back up my thinking that the SVS article is very biased. If a speaker has a small spider and VC, attached to a huge cone and low BL pole piece, the "warping" the article gleefully says is likely to occur. It will not be a perfect pistonic movement. That 18 Sound has a 4 inch VC and probably a square wire coil that works in a very small gap, like my JBL 14" from 50 years ago...
Excuse me, but that simulation does not seem to correspond to what is ideal for that 18 Sound. It says "closed", for my bad English it is synonymous with "sealed".
" The 18LW2400 is an 18 inch extended low frequency loudspeaker designed for high SPL subwoofer applications in either a reflex, bandpass or horn loaded configuration."
And with DSP you can fix that almost 20hz drop no problem, but it's better to use a big cabinet than to go up +20 Db electronically.
Just my thoughts, and I only have secondary studies, I didn't go to university
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It's a nice pro driver. Might not be my first choice for a sub, though.
Like I said, it was just for example. I look forward to some simulation with an 18" speaker that measures +/- 3 Db ( F3) 20 Hz. No matter the type of cabinet construction, it's sure to be big ....
en.wikipedia.org
Josef Anton Hofmann - Wikipedia
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Generally a loudspeaker system's efficiency follows this formula, which is what Mr. Hoffman has defined.Like I said, it was just for example. I look forward to some simulation with an 18" speaker that measures +/- 3 Db ( F3) 20 Hz. No matter the type of cabinet construction, it's sure to be big ....
Josef Anton Hofmann - Wikipedia
Efficiency = [constant] x Vb^2 / f3^3
In words, the efficiency increases proportional to the square of the enclosure volume and decreases proportional to the cube of the low cut-off frequency.
A 100L enclosure is four times (square of two) more efficient than a 50L one. A speaker that cuts of at 60Hz is eight times (cube of two) more efficient than a speaker cuts at 30Hz.
That is why the lower you want the speaker to go, the larger/bigger they have to be, or more power you have to use.
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Speaking of big subs... quite a few years ago I built four double 18" subs for a friend. The woofers were JBL 2242Hs... 8 woofers in total. That was a lot of woofer. LOUD and punchy to be sure, but not my favorite sounding subs.
The second photo shows two port lengths I made. He could use four of one size or the other or a mix to achieve different alignments.
The second photo shows two port lengths I made. He could use four of one size or the other or a mix to achieve different alignments.
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Have you tested them? What was it you didn't like?
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