Baseballbat said:
Mr. Geddes was obviously wrong. Let it be about the error. What is correct instead?
Mr. Geddes brought the homogenious DifEq into discussion. The solution is linear! Seen from that perspective the decay is time independent, or it was not linear. In conclusion it is time independent. No shift, no changeing relatations amplitude/frequency wise etc.
You survived Your German beer experience? Congrats!
One more example on low frequency content of a DVD. I hope everybody is now convinced that in a multiple sub setup low frequency content from ALL channels has to be summed into the subwoofer channel AND cut from the mains (or re-fed into all channels) in order to
- preserve overall loudness of low frequency sounds
- avoid radiation of low frequency signals from a subset of all speakers
The Spirit; US 5.1; Chapter 27; 5:19 Min.; L, Center, R:
Best, Markus
- preserve overall loudness of low frequency sounds
- avoid radiation of low frequency signals from a subset of all speakers
The Spirit; US 5.1; Chapter 27; 5:19 Min.; L, Center, R:
An externally hosted image should be here but it was not working when we last tested it.
Best, Markus
markus76 said:
That's why I moved to the States–Germans are all beer-drinking hooligans
P.S. I believe in character, not in nationality.
Two guys stopped by here yesterday who lived in Germany. They picked up a pair of Abbeys because they could take them back on the plane with no shipping costs - basically paid for the trip!
There were both perfect gentlemen, highly inteligent and a pleasure to have over. I guess its not the Nationality, but the Personality!
gedlee said:
Lufthansa has non-stop round trip flights from Seattle to Frankfurt for under $500 last time I checked. Considering what it would cost to ship a loudspeaker to Germany, that's a bargain!
Michigan is fun to visit too; I was thinking about taking a trip out there this weekend for Movement.
http://detnews.com/article/20090430...ement-festival-tickets-selling-at-a-fast-beat
Didn't you design a bandpass sub that uses multiple ports with different tunings?
There was a thread about this today:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=144331
There was a thread about this today:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=144331
I think that is a bad idea. Being so symmetric they are basically strongly correlated. For example they will cancel one mode but double another and not see some other modes at all. You don't want this kind of absolute all or none situation. What you want is a more random mixing of the sources so that the "average" source effect in the room is more uniform.
angeloitacare,
IF the room has rigid walls and IF the room is rectangular, then placing one sub at the front wall and one at the back wall might be better. See http://www.harman.com/wp/pdf/multsubs.pdf
Having more subs might be even better as Earl already pointed out.
Best, Markus
IF the room has rigid walls and IF the room is rectangular, then placing one sub at the front wall and one at the back wall might be better. See http://www.harman.com/wp/pdf/multsubs.pdf
Having more subs might be even better as Earl already pointed out.
Best, Markus
Slimline car subs with ESP P48A EAS bass controller
Thought this might be of interest to people who want to try the multiple small subs theory.
I recently rearranged my sub setup. Previously I was using a pair of JBL SB-2 6th order bandpass, heavily tamed with a parametric equalizer to get the peaks out of the response. They were quite big and took up too much real estate in my fairly small/confined listening room so had to go.
I decided to take a bit of a gamble and try a couple of the new breed of slimline car subs, already housed in a small 07 cubic Feet (around 20 ltr) box. These are not cheap at around AUD250.00 each but if space is a premium worth looking at.
http://www.ryda.com.au/v/vspfiles/photos/Q1041SBOX-2.jpg
edit: 10" Pioneer TS-SW1041D in ready made enclosure.
They are not that sensitive around 82-84db but they have huge power handling. Instead of hooking them up to a crossover I wanted to overlap them into my mains ( http://minirig.org.au/2008/11/13/minirig-10-mid-high-with-10-waveguide-and-compression-driver/ ) which tail off around 100hz. I wanted to try the Elliot Sounds Project (ESP) P48 ( http://sound.westhost.com/project48.htm ) Controller in combination with the compact car sub to see if it would work.
I won't go into the detail of what the P48 does as you can read about it in the ESP article on the website. I just wanted to share my experience with this trial. It has worked amazingly well. On construction of the P48 board I configured it to the FS (43.5hz) of the driver and that was it.
The bass that is coming out of these tiny boxes is effortless, tight and not at all "single note". I'm still using a small amount of parametric EQ but no where near the lever I was using with the JBL SB-2. I have from around 25hz to 145hz frequency curve which blends in with the bottom end of my mains well.
I'm using a fairly powerful 400w per channel amplifier with them but actually probably don't need all that power, 150w per channel would do fine.
Generally very happy with the outcome
col.
Thought this might be of interest to people who want to try the multiple small subs theory.
I recently rearranged my sub setup. Previously I was using a pair of JBL SB-2 6th order bandpass, heavily tamed with a parametric equalizer to get the peaks out of the response. They were quite big and took up too much real estate in my fairly small/confined listening room so had to go.
I decided to take a bit of a gamble and try a couple of the new breed of slimline car subs, already housed in a small 07 cubic Feet (around 20 ltr) box. These are not cheap at around AUD250.00 each but if space is a premium worth looking at.
http://www.ryda.com.au/v/vspfiles/photos/Q1041SBOX-2.jpg
edit: 10" Pioneer TS-SW1041D in ready made enclosure.
They are not that sensitive around 82-84db but they have huge power handling. Instead of hooking them up to a crossover I wanted to overlap them into my mains ( http://minirig.org.au/2008/11/13/minirig-10-mid-high-with-10-waveguide-and-compression-driver/ ) which tail off around 100hz. I wanted to try the Elliot Sounds Project (ESP) P48 ( http://sound.westhost.com/project48.htm ) Controller in combination with the compact car sub to see if it would work.
I won't go into the detail of what the P48 does as you can read about it in the ESP article on the website. I just wanted to share my experience with this trial. It has worked amazingly well. On construction of the P48 board I configured it to the FS (43.5hz) of the driver and that was it.
The bass that is coming out of these tiny boxes is effortless, tight and not at all "single note". I'm still using a small amount of parametric EQ but no where near the lever I was using with the JBL SB-2. I have from around 25hz to 145hz frequency curve which blends in with the bottom end of my mains well.
I'm using a fairly powerful 400w per channel amplifier with them but actually probably don't need all that power, 150w per channel would do fine.
Generally very happy with the outcome
col.
One thing that hasn't been discussed yet is the low frequency level distribution within a smoothed sound field created by multiple subs.
The low frequency level on every seat will be more or less the same whereas the level of the mains falls with increased distance. So we end up with low frequency levels that are too high or too low depending on which seat we're looking at. The difference might not be insignificant (≈6dB?)
Best, Markus
The low frequency level on every seat will be more or less the same whereas the level of the mains falls with increased distance. So we end up with low frequency levels that are too high or too low depending on which seat we're looking at. The difference might not be insignificant (≈6dB?)
Best, Markus
