Thanks for posting, but interpreting the graphics does not show an obvious/huge difference to me (as I would’ve expected).
a dipole bass stimulates the room more evenly, you don't have to struggle with standing waves. it cannot produce any physical pressure on your body because it does not work against an air mass in the housing. therefore he calms down quickly after the impulse.
mostly only baffle step has to correct, in the bass very few problems. the driver selection is crucial in the bass more then qts 0.8
mostly only baffle step has to correct, in the bass very few problems. the driver selection is crucial in the bass more then qts 0.8
Wow! Very cool! Thank you. Yes, I kinda remember reading about that and dropping the idea of living in the street while the subwoofer remained in the living room!
In addition, the Velodyne DD18+ (servo sealed sub) we use now is pretty much cut off above 36-38hz...as we really allowing the main speakers to go full range and then adding a gentle 'stabilizing foundation' of sub-bass that provides spacial cues, and a sense of the venue...plus some reinforcement during Hans Zimmer soundtracks, deep house/electronic, etc. It sounds like if we are looking to experiment with even lower distortion, greater air movement capability...then servo sealed or this dual-cone (Funk 18.2) seem like the right place to start.
https://www.funkaudio.ca/store/p9/Funk_Audio_-_18.2_Custom_Order.html
I am sure there are differences, but I don’t see how you can interpret anything but frq. and phase on a subwoofer impulse response. For quality (slow, fast, etc.), you probably need to look at distortions, which is tricker to assess (probably need anechoic chamber)
WRT dipole bass stimulating the room more evenly, depends on placement. Also it can create physical pressure - irrespective of the driver enclosure, or lack thereof pressure is created or there is no sound. is it the same effect as a driver in a cabinet - no, but again it depends on sub placement. be careful with broad generalities..
For me there is a big difference whether the sound works in one direction to the listening position like a normal subwoofer, or the sound is emitted in both directions with a dipole. both can be fun, for me the dipole is the favorite because it is easier to integrate into the room. assuming there is space in the room
Why people are even looking at this and not really putting it into real terms? And are they associating this with building a bass reflex box in the first place?My subwoofers are all "slow". I know this because I usually can catch up to mine in a dead heat, with favorable winds.
But seriously, I do see this subject crop up all the time. I'm sure it has been discussed before in different threads, but I'm feeling ambitious today and thinking maybe I could finally put the idea to bed. Or, maybe someone can convince me the idea has merit, in which case I will have to eat crow
Because they are not even mentioning speaker unloading, nor diver motor strength, just impulse response which is more of a function of electrical dampening that is going to change with what kind of amp is connected.
No crow feeding time, it sounds like you been observing some audiophile fiction to me.
Old thread. Look up Todd Welti; he knows a thing or two. E.g. https://www.harman.com/documents/multsubs_0.pdf
Nice read.
Another variable in room acoustics that can effect mode propagation is temperature and humidity. But this might be a little out of scope since the listening area is inside and theoretically a temperature controlled environment. So it would have a certain mean characteristic of acoustical wave conduction/resistance.
Another person to look up is Henry Bolt and the way he determined good ratios for a listening area. This is where the phrase 'Bolt Area' came from. Which is an interesting concept because it dealt with a handful of modes (in ratio relation) instead of calculating every mode. Of course today we have computers that can do it all.
One interesting site I came across a few years ago is a room simulator with a graph that you can mouse over and it would generate a sine wave at that mode frequency which is a handy tool to compare effectiveness in acoustic treatment.
amroc - THE Room Mode Calculator
HTML5 room mode calculator. Read and hear the tune of axial, tangential and oblique modes. Scientific sources included.
amcoustics.com
Todd is the OP of this thread just to be clear.Nice read.
Another variable in room acoustics that can effect mode propagation is temperature and humidity. But this might be a little out of scope since the listening area is inside and theoretically a temperature controlled environment. So it would have a certain mean characteristic of acoustical wave conduction/resistance.
Another person to look up is Henry Bolt and the way he determined good ratios for a listening area. This is where the phrase 'Bolt Area' came from. Which is an interesting concept because it dealt with a handful of modes (in ratio relation) instead of calculating every mode. Of course today we have computers that can do it all.
One interesting site I came across a few years ago is a room simulator with a graph that you can mouse over and it would generate a sine wave at that mode frequency which is a handy tool to compare effectiveness in acoustic treatment.
amroc - THE Room Mode Calculator
HTML5 room mode calculator. Read and hear the tune of axial, tangential and oblique modes. Scientific sources included.
I have used primed dimensions where possible to reduce the impact of room modes (golden ratios are another scheme) that aim to space modes apart in frequency and avoid "doubling" of modes in the room. I normally use the usual conventional formulae to calculate a rectangular room, or the Harmon calculator (spreadsheet), but have played with the amroc simulator (my room is asymmetric) and used COMSOL (wave analysis) and Matlab (mainly FEM like amroc) programs in the past. I still have Matlab, with a number of toolboxes for analysis, but have not played with it lately.
I am very familiar with the impact of temperature and humidity on sound propagation, as well as altitude, but mainly for tuning my trumpet rather than my room.
I am not familiar with Bolt Area though it seems to ring a bell. Acoustics was not my day job. But a quick search came up empty; do you happen to have a link?
Ha-ha! Zombie thread, back from the dead.
I don't think one should get bent out of shape about "slow bass". It's a useful concept, as long as people using it understand what it means. "Slow bass" is primarily an audiophile term, and audiophiles have a pretty good idea in general of what it means subjectively, even those who only have a rudimentary idea as to why.
There are some obvious things that lead to the perception of slow bass; poor cabinets and/or woofers and room modes. These are things an audiophile would know. As to what makes a poor woofer, audiophiles wouldn't likely know.
I use a stereo pair of 10" subs, which I bought because of their reputation for being "musical". But I can easily destroy their musicality with the wrong crossover point, phase control, or EQ.
The main thing is, slow bass is easy to diagnose. The bass is supposed to drive the music. If the bass seems to lag behind or drag, then it impacts on the musical involvement. The sound is there, but the emotional connection, the intense interest that music can generate, is compromised because the music ain't got that swing.
I don't think one should get bent out of shape about "slow bass". It's a useful concept, as long as people using it understand what it means. "Slow bass" is primarily an audiophile term, and audiophiles have a pretty good idea in general of what it means subjectively, even those who only have a rudimentary idea as to why.
There are some obvious things that lead to the perception of slow bass; poor cabinets and/or woofers and room modes. These are things an audiophile would know. As to what makes a poor woofer, audiophiles wouldn't likely know.
I use a stereo pair of 10" subs, which I bought because of their reputation for being "musical". But I can easily destroy their musicality with the wrong crossover point, phase control, or EQ.
The main thing is, slow bass is easy to diagnose. The bass is supposed to drive the music. If the bass seems to lag behind or drag, then it impacts on the musical involvement. The sound is there, but the emotional connection, the intense interest that music can generate, is compromised because the music ain't got that swing.
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