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Discussion in 'Archived Threads 2001-2004' started by felix_suwarno, Feb 17, 2002.
i am just curious. the bostons got nice reviews at audioreview.
the pv1000 is nice sub and small footprint. i listened to this sub when i was shopping for a sub upgrade. however if you want something that goes loud down to 20hz then it might not suit your need. i upgraded my pdr12 to servo15 and im very happy with my decision.
FYI: I've really been working with the PDR-10 lately, and I've found something interesting: turning down the cross-over on the sub really allows you to boost the low-end, and flattens out the frequency repsonse curve (FR).
I found this info at http://www.audio-ideas.com/reviews/h...gm-stylus.html . The FR chart shows that, by moving the sub's cross-over down to 90Hz (I use 100Hz), that you can turn up the sub, and thus the low ranges, without adding to the 40-100Hz range. I've checked this out on my sub, and the FR results are very flat, less a room induced lull at 45Hz that I would need an equalizer to remove.
Now, this is not an SVS but for my room I've still only got the sub's power dial at 60% -- so it works for me. It also helps if your mains can go down to 40Hz, allowing you to set the receiver's cross-over at 80Hz. Per a previous post, it is my understanding that setting the sub's cross-over at 100Hz should not step on much of the LFE signal, as this (per specs) has a hard stop at 120Hz.
John, I've taken a quick look at that article, I don't think it is saying what you think it is saying. It also doesn't explain well enough how he set things up, and makes at least one incorrect statment.
You should use one and only one of the following:
1)Receivers crossover for the sub (sub set to yes on receiver and one or more speakers set to small, really all your speakers should be set to small though).
2)The subs own built in crossover (sub set to no on receiver, main L/R must be set to large).
If you are using 1, then you want to defeat the crossover built into the sub. If there is an input that bypasses the crossover on the sub use it (I'm not sure if the line level input on the PDR10 does this or not). If there isn't an input that bypasses the crossover then you should turn the crossover as high as it can go. If you have both crossovers operating in close to the same frequency range they will cascade with each other, the results of which will be very bad.
If you are using option 2 then this means you are running your main channels through the sub. So the sub should be set to no on the receiver and the main channels to large. I won't explain this option further since unless you have some very specific goals with a two channel audio system I would not recommend using it.
I highly recommend this article to learn more about the LFE channel:
i cant turn the crossover down. my speakers are cinema 70. lowest freq is about 80 hz.
I suppose I should also answer your orignal question rather than just responding to another posters response.
I would say out right no. The performance gain would be none (PV600 is equivalent to the PDR10) and miminal (PV800 would be equivalent to the PDR12).
I would say Paradigm is being pretty optimistic about the frequency extension of its Cinema series speakers. I'd be hesitant to cross them over at 80hz. If you reciever has a selectable crossover frequency, I'd go up to 100hz or 120hz. This should prevent a hole in the frequency response between the sub and sats, but it will make the sub more localizable.
I would take whatever money you were going to spend on a sub and put that towards upgrading your speakers before you upgrade the sub.
If you know you will never pass a certian budget point, save for that budget point and buy the best speaker you can with it. But don't go and buy the Paradigm Monitor series if you think a year later you will be able to justify the Reference series. Live with what you have now and save for what you really want, not a bunch of stop gaps that will just end up costing you more money in the long run.
For reasonable budgets I'd also be taking a look at Diva, nOrh and Axiom for my speaker upgrades. Five nOrh 4.0 speakers mated to a Rava or whatever SVS's new PCi is gonna be for right around $1250 would make an great compact speaker system.
my receiver would be a denon avr2802. is it possible to raise the crossover? usually i turned the knob on pdr10 to maximum level / the crossover, not the volume knob.
According to Denon's site the 2802 has a selectable sub crossover. The settings are 80hz, 100hz or 120hz.
The 2802 is a great receiver. The PDR10 is a respectable sub. The Cinema series speakers aren't anywhere near the same league as your other equipment.
As for how you have set the PDR10's crossover, perfect. Now just read the manual for your 2802 and get the crossover set to 100hz if it isn't already there and start saving for some better speakers.
John, I owned a PDR10 before I built my Tempest Sonosub. I had no audible 20hz output from it with a test tone. The PDR10 rolls off heavily and very quickly below 30hz.
I didn't have an SPL meter at the time I ran these tones. However, I could barely hear the 20hz sine wave out of my Sonosub, but I sure could feel it and see things shaking. With the PDR10 I got nothing, couldn't hear or feel anything.
I'm not positive on this, but I do believe the crossover on the PDR10 will a 2nd order one. 12dB/octave is not going to prevent cascading between a 100hz and 80hz crossovers.
I know a highpass filter can cause a frequency boost to the frequencies above it. I've never heard of a low pass filter causing a decrease in ouput to frequencies below it though which is what you are suggesting. I'm gonna ask this question in the DIY Advanced section since my knowledge of the intracasies of crossovers isn't that great.
Running the LFE "stand alone" sweep (Avia), a 100hz crossover on the sub and adjusting for the RatShack SPL at 85hz (target), I got:
Hz -- db's
80 -- 76
75 -- 80
70 -- 86
65 -- 86
60 -- 85
55 -- 85
50 -- 83
45 -- 80
40 -- 85
35 -- 88
30 -- 85
25 -- 80
20 -- 79
Running the "sub sweep" (not LFE only) gets similiar results, but with a flatter curve at the top where the front's kick in.
So, yes, there is a falloff below 30hz of 5db's in my room, but there is output.
Can you run that sweep again, but this time get the 70hz up to 100dB (you may want to pick up some ear plugs before you try this one) and then run down to 20hz.
I received a SPL meter for christmas this year. My Avia disk also finally arrived after 6 weeks of waiting. Problem is I'm on my spring break and at my parents place (who now have my PDR10) and my SPL meter is back where I go to school, and the Avia disk is still at the store I ordered it at (it arrived the day after I left on my break, figures :p)).
Oh, and also, what size of room are you in? You said the sub was in the middle of the room right? Finally where was the RatShack meter when you were taking those measurments (right infront of the sub, 1m from sub, listening position or other)?
If you redo that measurement for me I'd like to see it done from the listening position.
I'm on the road, so I will not be able to run the test. Also, I'm not quite sure how to accomplish it. The Avia LFE sweep only starts at 80hz. The Avia Sub sweeps have no LFE output, so they will be impacted by the crossover in the receiver.
This is different from the two curves built by the reviewer:
Also, please note that one is not "increasing the lowend db's" on this sub, but eliminating the high end volume hump -- getting a flat response curve. The net effect for me was that, instead of calibrating the sub at 1/2 on the sub volume dial, I set the crossover at 100 and the sub calibrated at 2/3's on the sub's volume dial. In other words, I eliminated the boom at the top high of the output curve, allowing more output at the bottom end. It also seems to get an additional 3db's at the 22hz level as of result (per the attached curve).
My sub is 7' from the listening position, and happily I have a delay setting available for the sub in my receiver to integrate this with the soundstage. The room is odd: ~25' x 15', but the 5.1 listening area is on one side with a dimension 13' x 8'. All SPL readings are from the listening position.
Well, I'm gonna try and steal my PDR10 from my parents and head back from my break a little earily and run some of these measurements in my room since I know the Avia disc is waiting for me.
I'll try 4 things, all measured from the seating position:
sub in corner, reciever 80hz, sub 150hz
sub in corner, receiver 80hz, sub 100hz
sub in middle of room, receiver 80hz, sub 150hz
sub in middle of room, receiver 80hz, sub 100hz
If I manage to make it happen, I'll post my results on Friday night or sometime Satarday.
Remember to re-balence the speakers if you change the crossover setting and/or position. Turning down the crossover also decreases the overall volume output. I was able to get away with this as I had plenty of headroom on the sub in my setup.
Don't worry, I intended too. Testing like this doesn't mean much if you don't level match the different configurations.
Schedule got put back a day. Finally got back and picked up my Avia disc.
So much for frequency response graphs off of Avia. I don't think you can get an accurate graph off of the sweeps given they are always changing and move to fast. I'll eventually get a proper bass test-tone disc (individual frequencies for 10-30seconds on seperate tracks). But guess it will have to wait until then.
I do have a pretty nasty room mode at 40hz and a null at 80hz though
Response doesn't drop off at all (taking into account correction values), all the way down to 20hz though
I just ran the sweeps with the PDR10 instead of just my Tempest at matched levels (around 85dB at 90hz). The PDR10 dropped off 10dB more than the Tempest as the sweep went below 25hz. I then took it up closer to 100dB and the Tempest showed the exact same drop off while the PDR10 dropped off 5dB further (this is referencing uncorrected numbers, so really the Tempest just didn't drop off, and the PDR10 dropped down 10dB or so). The PDR10 was straining pretty bad at this point, so I didn't go any higher with it. I took the Tempest a little higher, but it got scarry (my windows are old).
I also finally took the measuring tape and measured the port in the PDR10. It is 3" in diameter and 7" long. The sub itself is 13.5x13.5x15 inches. Even assuming only 1/2" sides with no bracing that would lead to an internal volume of just over 2300 cubic inches. Even if you only dropped it to 2000 to account for the displacment of the driver and port that is 32.5L. At that volume the PDR10 would be tuned to 41hz. Paradigm reports the volume as 37L, which might be possible with the appropriate stuffing, but still over generous. At 37L the 7" port would tune it to 38.5hz.
That is a really high tuning frequency for a sub. I'm utterly amazed that I read the output I did from it below 30hz with that tuning frequency. There must be a chunk of boost around 30hz to keep its output up that high at and just below 30hz.
This link is a good read if you want to learn what a port does: