Well, I don't even have that space, since there's a huge living room shelf, and there's no space left on the floor!
This what I came up with. Really enjoyable.
They will get real enclosures soon. The foam boards are for quick design experiments.
Thread: http://www.diyaudio.com/forums/full-range/301601-small-ob-fast-setup.html
This what I came up with. Really enjoyable.
They will get real enclosures soon. The foam boards are for quick design experiments.
Thread: http://www.diyaudio.com/forums/full-range/301601-small-ob-fast-setup.html
I have been playing with my OB for a while, watching Real Steel or Transformer (especially when the chopper scene on first attack on the base) have never been like this fun. Huge sound and feeling the impact, sometimes i think that i hear it better than a Cinema with THX where the bass will shake the chair but my ear dont fell any effect. That is where OB bass excells at.
but... now I feel that 15" woofer and 20" baffle is small, so new plan comes. It will be using 24" baffle and two 18" woofer from top class of ACR, not like my current 15" woofer from low grade one
18″ PA 100182 SW FABULOUS BY ACR | ACR Speaker
I also got nos driver Fostex F346, maybe additional ribbon will be great.
is there any formula to design the slot for 18"? or can use same slot as original Papa design with additional width?
but... now I feel that 15" woofer and 20" baffle is small, so new plan comes. It will be using 24" baffle and two 18" woofer from top class of ACR, not like my current 15" woofer from low grade one
18″ PA 100182 SW FABULOUS BY ACR | ACR Speaker
I also got nos driver Fostex F346, maybe additional ribbon will be great.
is there any formula to design the slot for 18"? or can use same slot as original Papa design with additional width?
Attachments
Last edited:
I'm glad someone else has finally also observed this.
For years playing bass guitar, I have never been satisfied with the response of a single 15".
2 x 10" is so far superior than a single 15" it's not funny.
The cross sectional area of the slot should be 1/3 the cone area of the woofer.
Response to #150
Glad you agree, but i think you are wrong. For subwoofer duty - the larger the better.
If you play an instrument, then it's another purpose. 15" and 18" will not play very well high in frequencies. I play guitar and have tried Altec 15" with alu dome, but it was not as good as a cheep 12", but it was louder
15" and 18" will play considerably lower without stress, and that can be seen/heard as slow bas, but it's definatly not the case. There is absolutely no reason why it should be slow, but there is plenty of reason why it's not good for bassguitar and electrical guitar.
Glad you agree, but i think you are wrong. For subwoofer duty - the larger the better.
If you play an instrument, then it's another purpose. 15" and 18" will not play very well high in frequencies. I play guitar and have tried Altec 15" with alu dome, but it was not as good as a cheep 12", but it was louder
15" and 18" will play considerably lower without stress, and that can be seen/heard as slow bas, but it's definatly not the case. There is absolutely no reason why it should be slow, but there is plenty of reason why it's not good for bassguitar and electrical guitar.
It's about facts not opinions
SoundStage! Max dB - Fast Bass, Slow Bass - Myth vs. Fact (06/1999)
And I do agree with you if the 18" are also used for midrange, but if used as a subwoofer below 80 Hz, then it's a fact that it's not slow. 20-80 Hz are slow frequencies. A really bad woofer with very high Qts and very small magnet will of course sound bad/slow and with lot of distortion. I only refer to good quality woofers, when I say that they are not slow.
SoundStage! Max dB - Fast Bass, Slow Bass - Myth vs. Fact (06/1999)
And I do agree with you if the 18" are also used for midrange, but if used as a subwoofer below 80 Hz, then it's a fact that it's not slow. 20-80 Hz are slow frequencies. A really bad woofer with very high Qts and very small magnet will of course sound bad/slow and with lot of distortion. I only refer to good quality woofers, when I say that they are not slow.
It's about facts not opinions
SoundStage! Max dB - Fast Bass, Slow Bass - Myth vs. Fact (06/1999)
And I do agree with you if the 18" are also used for midrange, but if used as a subwoofer below 80 Hz, then it's a fact that it's not slow. 20-80 Hz are slow frequencies. A really bad woofer with very high Qts and very small magnet will of course sound bad/slow and with lot of distortion. I only refer to good quality woofers, when I say that they are not slow.
Again based on my experience 12" vs 15",
So I guess at this point you must start a thread about this specific topic.
I can't play any music instrument or sing properly (I hate karaoke) but my ear taste on music is good
regarding slow or fast bass, am i correct that guitar only produce mid bass? something that is not a duty for 18" subwoofer but more to 10" or 12" midbass.
my current 15" woofer is listed as fullrange, I dont use any filter and only use LC filter for Alpair to limit low freq. Without any Eq, the bass is very thin but when eq applied then it shows it's muscle.
The history of my plan to use this dual 18" subwoofer is that when I visited local part store, he has some old stock Fostex F346, 12" fullrange up to 7kHz and it was very good when I listen to it on baflle-less, so i thought this should be a good candidate for my next OB fullrange. Then 18" & 12" seems a good match proportionally on my eyes instead of 15" & 12"
12" FR is my dream but less choice available, I had been looking at audio nirvana 12" but hate to import it, and I only paid around $225 ~ JPY 25k for this F346 where it was listed as JPY 32k on it's brochure years ago.
regarding slow or fast bass, am i correct that guitar only produce mid bass? something that is not a duty for 18" subwoofer but more to 10" or 12" midbass.
my current 15" woofer is listed as fullrange, I dont use any filter and only use LC filter for Alpair to limit low freq. Without any Eq, the bass is very thin but when eq applied then it shows it's muscle.
The history of my plan to use this dual 18" subwoofer is that when I visited local part store, he has some old stock Fostex F346, 12" fullrange up to 7kHz and it was very good when I listen to it on baflle-less, so i thought this should be a good candidate for my next OB fullrange. Then 18" & 12" seems a good match proportionally on my eyes instead of 15" & 12"
12" FR is my dream but less choice available, I had been looking at audio nirvana 12" but hate to import it, and I only paid around $225 ~ JPY 25k for this F346 where it was listed as JPY 32k on it's brochure years ago.
Attachments
You need a large woofer with high Xmax and very little mechanical noise. Any woofer mounted on a narrow open baffle will need a lot of eq (low Q woofers need even more eq), and a lot of Xmax.
If you have the space for a very wide bafflen, the you don't need huge Xmax and not even huge woofers. As always there is no free lunch.
Just for fun, then try look at the sensitivity at 25 Hz for at 98 dB 15" woofer (low Q) and a 90 db 15" woofer (high Q). I bet they will be around 85 dB for both.
Then you also have baffle loss, so obviously we need Xmax and large woofers when making open baffle. The benefits are in the sonics and less room interactions (and I also ikke the looks of an OB)
For an 18" it might be around 90 dB.
If you have the space for a very wide bafflen, the you don't need huge Xmax and not even huge woofers. As always there is no free lunch.
Just for fun, then try look at the sensitivity at 25 Hz for at 98 dB 15" woofer (low Q) and a 90 db 15" woofer (high Q). I bet they will be around 85 dB for both.
Then you also have baffle loss, so obviously we need Xmax and large woofers when making open baffle. The benefits are in the sonics and less room interactions (and I also ikke the looks of an OB)
For an 18" it might be around 90 dB.
It's about facts not opinions
SoundStage! Max dB - Fast Bass, Slow Bass - Myth vs. Fact (06/1999)
And I do agree with you if the 18" are also used for midrange, but if used as a subwoofer below 80 Hz, then it's a fact that it's not slow. 20-80 Hz are slow frequencies. .
Yes this also use to confuse me.... but then my brain turned on.
20 to 80Hz is slow, but when you multiply that by the linear cone excursion at bass frequencies (being orders of magnitude greater than at higher frequencies of the mids and treble) the actual linear velocity of the cone is actually quite high. This is one point people haven't seemed to consider at all.
I also wonder about the apparent stiffness of a cone due to aspect ratio changes as you go up in diameter, ie to maintain structural stiffness, thickness would also need to be increased, affecting moving mass considerably, and if not accounted for I suspect higher distortion would be the result, fine for special effects in movies, possibly not ideal for music. This isn't something I have had a chance to personally test out though, so possibly (even likely) not quite right.
I'm certainly not disagreeing with you just sharing my own thoughts, except my definition of a subwoofer is sub 30Hz, certainly not as high as 80 Hz. I'm not a fan of getting super pedantic about sub 30Hz as it tends to create it's own problems ie everything that can resonate will resonate, doesn't sound nice at all if you have that scenario occurring.
Last edited: