Port resonance is the total of the area x length.
Yes it is always nice if you can move the frequency higher unless you can get it so low it is below the audible range but that won't normally happen.
Yes it is always nice if you can move the frequency higher unless you can get it so low it is below the audible range but that won't normally happen.
yes and when you use the spacers full length , then what? the behavior is no longer 1 port, best to space equally ?
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Doh!
Sorry, this was years ago; wired in phase with the drivers reversed, a la S1C, wired out of phase a la S1B.
Sometimes I text faster than my brain.
MITsound; said:
Sorry, this was years ago; wired in phase with the drivers reversed, a la S1C, wired out of phase a la S1B.
Sometimes I text faster than my brain.
As frequencies go up there is also less energy to excite panel resonances, and the relative panel thickness is greater. Get the panel resonance (potential) high enuff and the music will not be able to excite them. As well, if you can make the potential resonances high Q, they need significant continued energy across a very narrow bandwidth to excite them, something that is rarely seen in music. And with high Q resonances less audiable then low Q resonances (Toole) if they do get excited they are less audiable.
dave
The sum of the vents is what tunes the box, so yes you could do this. In one of our plansets there is a variation on this idea intended to reduce the potential of a resonace found in an actual build.
dave
Thread where my box construction techniques are discussed.
http://www.diyaudio.com/forums/cons...ussion-what-materials-build-speakers-out.html
dave
http://www.diyaudio.com/forums/cons...ussion-what-materials-build-speakers-out.html
dave
I gotta say, these are great posts, people. Thanks for sharing; it's a pleasure learning from you all.
Planet10 is right about being able to use different area vents together, you just add the total area together. The problem is when you use different lengths, then it is not the average of the different lengths, the shortest length sets the tuning.
Kindhornman, in terms of materials behaviour could you explain what's going on here - IOW, where is the damping coming from?
Thanks,
Frank,
The cast aluminum is actually more rigid, it has a different molecular structure. Cast aluminum density is lower. If I was a chemist I could explain this better, perhaps SY can chime in if he is reading this. Forged aluminum is much denser and the material properties are more uniform in all directions vs the cast aluminum.
The cast aluminum is actually more rigid, it has a different molecular structure. Cast aluminum density is lower. If I was a chemist I could explain this better, perhaps SY can chime in if he is reading this. Forged aluminum is much denser and the material properties are more uniform in all directions vs the cast aluminum.
NOT all omni speakers are created equal heck some speakers called omni are not since they dont have a near perfect power response in 360 degrees. You cannot judge omni from 1 speaker as you know.
Thanks for that, Kindhornman - I suspected that the working of the material would make it more homogeneous, and hence prone to ringing.
However, look at table 4 in this - and weep: Mechanical Properties of Gray Iron - Damping Capacity
We're using the wrong material, 😉 ... !
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Thanks Sy.
Frank just try and move a speaker cabinet made of cast iron, not a pretty thing! I have some 500 lb granite enclosures, takes two people and a dolly to move them. They are so thick then are actually really dead. but I have seen granite and marble sing real nice.
Frank just try and move a speaker cabinet made of cast iron, not a pretty thing! I have some 500 lb granite enclosures, takes two people and a dolly to move them. They are so thick then are actually really dead. but I have seen granite and marble sing real nice.
I may not have stated my position clearly, i like to keep the port spacers equidistant on a full length port like that, output at the ends are always greater, rigidity in the center most important ..
Hi and just to clarify the speaker in question was one from MBL
to me it is perfectly omni, maybe i am wrong
The sound was unbelievably clean and transparent
The image was no existing with the voice of the singer coming from all around
It was like to be surrounded by just one person ... unacceptable to me.
I like to "see" the singer in front of me, almost physically.
I like a "tactile" image.
I want to walk around the singer.
Thanks and regards, gino
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Hi and thanks a lot indeed to All of you for the very interesting and valuable advice.
One way to simplify things, i believe, is to go for a sub + satellite solution
Obviously the main vibrations generator is the woofer
I understand that very good subs can be found and not extremely heavy
The sector has improved immensely due to the requirements from high end HT applications
Sending to the satellites only the upper part of the range (from 150 Hz up) should make the vibrations issue much less critical
So the satellite can be more "human"
This is what i have in mind actually
And also not requested to reproduce lower frequencies the satellites should have also less distortion.
About the xover cut between low and mid i see many designers for 3 ways speakers setting the cut frequency around 150 Hz.
This is a very fundamental design choice
It separates the slow bass from the fast bass.
150 Hz seems a very reasonable choice.
Moreover someone says that the minimun number of ways to reproduce all the audio range with conventional drivers is 4:
- low bass
- bass
- mid
- high
I tend to believe them
Thanks again and regards,
gino
One way to simplify things, i believe, is to go for a sub + satellite solution
Obviously the main vibrations generator is the woofer
I understand that very good subs can be found and not extremely heavy
The sector has improved immensely due to the requirements from high end HT applications
Sending to the satellites only the upper part of the range (from 150 Hz up) should make the vibrations issue much less critical
So the satellite can be more "human"
This is what i have in mind actually
And also not requested to reproduce lower frequencies the satellites should have also less distortion.
About the xover cut between low and mid i see many designers for 3 ways speakers setting the cut frequency around 150 Hz.
This is a very fundamental design choice
It separates the slow bass from the fast bass.
150 Hz seems a very reasonable choice.
Moreover someone says that the minimun number of ways to reproduce all the audio range with conventional drivers is 4:
- low bass
- bass
- mid
- high
I tend to believe them
Thanks again and regards,
gino
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Hi and just to clarify the speaker in question was one from MBL
to me it is perfectly omni, maybe i am wrong
The sound was unbelievably clean and transparent
The image was no existing with the voice of the singer coming from all around
It was like to be surrounded by just one person ... unacceptable to me.
I like to "see" the singer in front of me, almost physically.
I like a "tactile" image.
I want to walk around the singer.
Thanks and regards, gino
Yes that is the speaker I was hinting at. When I heard them I could walk around and see the performers very realistic. The setup could have effected it but oh well we will never know. My clones also require some care to not sound like that. I have actually spoken about this phenomenon to someone. The imaging can be stellar but in some cases its like you said I have not quite laid my hands on the magic that's causing it yet.
Yes, it is the setup. The "phemonenon" is that the electronics are not adequate, too much of the low level detail is being lost, or 'smeared' if you like. The best speakers in the world will fail miserably to convince if not driven cleanly - it's a system issue, and always will be. As long as one focuses on only one, or two, components being the "everything" behind the 'magic' then one is also almost guaranteed to have, at the best, only a feeble grasp on getting top notch sound every time.
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