I don't think it is impossible. Look at the graph.Quote:
Originally Posted by yggdrasil
Attachment 53654
Printable View
I don't think it is impossible. Look at the graph.Quote:
Originally Posted by yggdrasil
Attachment 53654
The "problem" is "dotted-line" which is usually 45 deg "off-axis" response, or better to say,Quote:
Originally Posted by Lee in Montreal
large driver tends to "beam". Under such you have -5dB on 800Hz
I think it would be better to look here:Quote:
I don't think it is impossible. Look at the graph.
http://www.audioheritage.org/vbullet...hp?10654-2245H
Rob:)
I'm not sure about all the different models of speakers JBL made, but there's not many places the 2245 was used as anything but a subwoofer. The 4345 used a 2245, and crossed it out at 290Hz (I think, seems like 320Hz is another figure floating around in my head), but much lower than 800Hz.
Hello Jeff
Yes and if you look at the impedence curve in the referenced measurement you can see jogs at the dip and peak after 500Hz which is probaly why this is so.
Rob:)
Unfortunately, there is no "off-axis" response, but I think it is expect-able that over 500Hz, off-axis response stat to 'decline'Quote:
Originally Posted by Robh3606
Build the 12 ft³ version, that way when you get your fingers out of your ears after your primary listening experience you will have the real-estate to add a dog box and a 10" or 12" driver. :p
I always find it odd that many people worry about off axis response but when they build a listening room, the seating position is always smack on axis.....:blink:
Allan
Yes, swet spots sucks, and if the "direct / reflected of the walls" combination is important to you, then it becomes important.Quote:
Originally Posted by Allanvh5150
Who mentioned a sweet spot? I just do not recall any listening rooms where the speakers are pointing at some angle.Quote:
Originally Posted by Eaulive
Allan.
May be for some other members it would be interesting to read Dr. Earl Geddes paper which is dealing with the Speaker DirectivityQuote:
Originally Posted by Allanvh5150
http://gedlee.com/downloads/directivity.pdf
and this too:
http://decoy.iki.fi/dsound/ambisonic...Kates_1980.pdf
For my personal experience: I do not like to "directiv" speakers
Do you mean facing straight ahead with no toe in towards the listener?? Mine sure are. I have toe in on all three of my fronts and my mains for the stereo rig.Quote:
Who mentioned a sweet spot? I just do not recall any listening rooms where the speakers are pointing at some angle.
Rob:)
I am surprised you haven't previously seen listening rooms with speakers angled toward the listener's seat. I've been doing it for the past 30 years and as far as I remember, I even think it is how most systems are installed. After all, isn't it what "on-axis" is about? :DQuote:
Originally Posted by Allanvh5150
Back to the 10 vs 12cft topic, I managed to grab a simulation "software" to work on my Mac. Basically, nothing more than an Excel spreasheet but good enough. The difference between 10 and 12cft is not more than perhaps 2 Hz in F3 and Fb, reduced 50Hz SPL and increased excursion when feeding 350w.
That's the point I was making. It took you what 5 minutes if that to find the answer you were looking for.Quote:
I managed to grab a simulation "software" to work on my Mac.
Rob:)
Actually, it gave me some clues, but didn't answer all my interrogations. Per exemple, the ports is de facto tuned to Fb. I can't find how to tune the port to the driver's Fs 20Hz, or somewhere between Fs and Fb.Quote:
Originally Posted by Robh3606
So far it goes like that. 10cft vs 12 cft tuned at Fb 27,3Hz
Response. The thin green line is the gain/loss between 10 and 12 cft
Attachment 53670
Excursion at 350w
Attachment 53671