Very Impressive.
All those who requested the file should have received it - however I must warn you that it is big. Converting it from a doc to PDF moved it from 2.5M to 7M so I left it as a doc!
Mark, as some ppl around here know - my hearing is not great and I don't pretend it is (as a result of a sub-aqua diving incident). It doesn't matter whether I agree if something can be heard or not - but what does matter is that I have built it to the best of my ability. Decreasing distortion by 5-10% and keeping response flat to 20-25Hz using an 8" DVC is unheard of - at least to me. The only exceptions that I could believe is using active circuits. However, most don't use feedback, so actually add to distortion, not reduce it. Like I said, whether I can hear a difference doesn't matter - it's the building for me and probably alot of people. Everyone likes to over engineer and impress. How many members finish a project then pack away their soldering irons and woodworking tools because they're happy with the sound?
For me, the attraction is a circuit that requires little tuning and can therefore be added to any DVC driver, with the same effects (substantially reduced distortion, much improved FR and far better accuracy). This will account for any inaccuracies in speaker building, such as a slightly off volume estimation or air leak etc.
Anyway, although I haven't number crunched your figures, the Adire Tumult has a massive 68mm p2p xmax, which I'm sure is more than enough to move some air from this 15"!
I'm not saying you're wrong at all, but it isn't my aim to hear 16Hz, just be able to produce it if I can, whilst getting the most accuracy in the area I can hear.
Gaz
All those who requested the file should have received it - however I must warn you that it is big. Converting it from a doc to PDF moved it from 2.5M to 7M so I left it as a doc!
Mark, as some ppl around here know - my hearing is not great and I don't pretend it is (as a result of a sub-aqua diving incident). It doesn't matter whether I agree if something can be heard or not - but what does matter is that I have built it to the best of my ability. Decreasing distortion by 5-10% and keeping response flat to 20-25Hz using an 8" DVC is unheard of - at least to me. The only exceptions that I could believe is using active circuits. However, most don't use feedback, so actually add to distortion, not reduce it. Like I said, whether I can hear a difference doesn't matter - it's the building for me and probably alot of people. Everyone likes to over engineer and impress. How many members finish a project then pack away their soldering irons and woodworking tools because they're happy with the sound?
For me, the attraction is a circuit that requires little tuning and can therefore be added to any DVC driver, with the same effects (substantially reduced distortion, much improved FR and far better accuracy). This will account for any inaccuracies in speaker building, such as a slightly off volume estimation or air leak etc.
Anyway, although I haven't number crunched your figures, the Adire Tumult has a massive 68mm p2p xmax, which I'm sure is more than enough to move some air from this 15"!
I'm not saying you're wrong at all, but it isn't my aim to hear 16Hz, just be able to produce it if I can, whilst getting the most accuracy in the area I can hear.
Gaz
Didn't mean to rain on your parade
Sorry to come down so heavy handed. I've designed systems for almost twenty years and have heard these claims for at least as long. People who have heard the bass you are describing never forget it. I have built systems for clients that push out the required spls. Go for it and lets us know what you end up with. Awesome. I'm putting mine together over the winter. On the audire check the T/S parameters and then do a proper x-max calc and see what you get. I think last time someone drolled over it I came up with 42 mm ptp. DuMax can also be read as DuMarketing.
Mark
Sorry to come down so heavy handed. I've designed systems for almost twenty years and have heard these claims for at least as long. People who have heard the bass you are describing never forget it. I have built systems for clients that push out the required spls. Go for it and lets us know what you end up with. Awesome. I'm putting mine together over the winter. On the audire check the T/S parameters and then do a proper x-max calc and see what you get. I think last time someone drolled over it I came up with 42 mm ptp. DuMax can also be read as DuMarketing.
Mark
Re: Didn't mean to rain on your parade
Don't worry - you didn't offend anyone...Just a good discussion.
"Never forget it" how? In a good way - or bad way. I don't want to spend £1000 on some new speakers that sound crap...But this good a good write up (granted - by the author)
So you're going to bite the bullet and have a go? Or is this an open loop system you're building.
Like I said, that Adire Tumult puts out 68mm ptp so more than enough headroom! Speakers have hardly changed since the '30s so when ideas like this come along (and become engineeringly viable) then I for one am very interested. This side of things has stayed passive and open loop for far too long. Who knows, maybe in 10 years, all systems will be closed loops, and 20yrs after that, everyone will return to open loop speakers and say what a breath of fresh air they are! Just like tube amps...
That's the way of the world in this hobby!
Gaz
mwmkravchenko said:
Don't worry - you didn't offend anyone...Just a good discussion.
mwmkravchenko said:
"Never forget it" how? In a good way - or bad way. I don't want to spend £1000 on some new speakers that sound crap...But this good a good write up (granted - by the author)
mwmkravchenko said:
So you're going to bite the bullet and have a go? Or is this an open loop system you're building.
mwmkravchenko said:
Like I said, that Adire Tumult puts out 68mm ptp so more than enough headroom! Speakers have hardly changed since the '30s so when ideas like this come along (and become engineeringly viable) then I for one am very interested. This side of things has stayed passive and open loop for far too long. Who knows, maybe in 10 years, all systems will be closed loops, and 20yrs after that, everyone will return to open loop speakers and say what a breath of fresh air they are! Just like tube amps...
That's the way of the world in this hobby!
Gaz
If you are truly crazy and want really low bass at high output, you need to look at a fan driven 'sub'. Basically, a fan moves air through a loop. There are two openings on the sides of the loop. In the middle of this opening, there's a flat plate that's connected to a servo motor. The servo motor is actuated by the music signal. So when the motor turns, the plate turns at an angle to the air stream, shunting it out of one of the openings and causing air to be sucked in the other opening. If you vent one of the openings to the outside or another room, and you have a well sealed room, you can pressurize the room (get response to DC). The fan just keeps pumping air into the room. The output level is limited by the amount of air the fan can move. These can be built for use below 30hz or so. The problem is that you get a lot of fan noise - air moving around and that sort of thing. So you would need to run the output through an acoustic low pass filter before it reached the listening room. You can find a patent describing this by searching for the name 'Danley'. He built a few for a sonic boom simulator, or something like that. They had 6 units running outside, each using 2 5HP 3-phase fans, and they were moving the walls of a nearby house about a foot peak to peak at 3Hz. You wouldn't need that much air flow inside, though.
John
John
Rarkov said:Very Impressive.
All those who requested the file should have received it - however I must warn you that it is big. Converting it from a doc to PDF moved it from 2.5M to 7M so I left it as a doc!
I am afraid i have not recieved the file
could you send it again please? matttcattt@yahoo.co.uk
thankyou
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