subwoofer cut off freq on pdr10

Discussion in 'Archived Threads 2001-2004' started by felix_suwarno, Jun 20, 2002.

  1. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    according to the spec, the cut off freq of the pdr10 is between 50 to 150.

    so.

    if i set the button exactly on 12 oclock, does that mean i cut the freq off at 100 hz?
     
  2. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    somebody please answer this!
     
  3. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
    That would make sense. If that isn't how it is, someone at Paradigm deserves to be shot.

    How are you hooking it up though. Sub preout, or are you feeding it the speaker level inputs in parallel (which is the only way you can use the speaker level inputs with the PDR10).

    If you are using the sub preout. I'd set all your speakers small, let the receiver worry about the crossover, and set the dial at 150hz on the PDR10 to essentially turn off its' lowpass filter.

    If you are using the speaker level inputs, then yes, use the PDR10's crossover.
     
  4. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    i am using sub pre out.

    why do you think setting it on 150 hz would be best? what is "low pass filter"?

    i set the crossover on the receiver to 80hz though.

    thanks
     
  5. Vin

    Vin Supporting Actor

    Joined:
    Oct 23, 2000
    Messages:
    546
    Likes Received:
    0
    Trophy Points:
    0
    Felix, as Dustin said, when using the pre-out from the receiver it's best to bypass the sub's crossover (low pass filter) as there's no need to use 2 crossovers at the same time. Don't forget, the LFE channel can contain information up to 120Hz so if you set the sub's crossover anywhere below 120Hz you could potentially be losing some info.

    Also, with your speakers set to small, anything below your receiver's crossover will be sent to the sub, so if you set the sub's crossover dial below the receiver's crossover you'll be creating a hole in the frequency response.

    Vin
     
  6. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    thanks vin.

    but i dont get it.

    my sat speakers, boston vr-m50 and vr-mc are said to be able to pull 59 hz.

    why do i need to set the sub cut off to, say, 120 hz? dont you think about 80 to 90 should be enough?

    besides, if i set it to the max, the sub becomes really boomy. now i think it sounds great, i felt like i just bought a new subwoofer.

    please explain.
     
  7. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
    I suggest you read this:
    http://www.hometheaterforum.com/htfo...602#post523602
    You want to disable the lowpass filter in the sub when using the LFE output of the receiver (setting the dial to 150hz is a way of doing this). You do not want two low pass filters (receiver and sub) interacting with each other, they can cascade and produce some undesireable effects. However, make sure all your speakers are set to small on your receiver (so their below 80hz stuff will be sent to the sub).
    As for the low end extension of your speakers, don't worry about that. You want a speaker to be flat to below where it is crossed over. You aren't wasting your speakers response. Subs do bass better than speakers. Let the sub do the bass. Also relieving your speakers of bass duty means they will require less power and will be able to play louder before distorting or bottoming out.
     
  8. Vin

    Vin Supporting Actor

    Joined:
    Oct 23, 2000
    Messages:
    546
    Likes Received:
    0
    Trophy Points:
    0
    Felix, I think the part you're not getting is this.....when using the subwoofer pre-out from the receiver and a sub setting of ON, the LFE channel is sent ONLY to the sub. So, as you adjust the sub's crossover (low pass filter) you're limiting what frequencies it will let in. What happens then is this.....if you set it at 80Hz the LFE info between 80 and 120Hz will be lost....it won't be routed to your mains or anywhere else, it's just lost. Get it?
    The other reason why you'd want to bypass the sub's crossover and set all your speakers to SMALL was already covered by Dustin.
    Bottom line though is to go with whatever sounds best to you. [​IMG]
    Vin
     
  9. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    what is lfe channel then? is it anything below 150 hz? what is the point of using big bookshelf speakers that go as low as, say, 60 hz if the capability is not used?

    i will follow you guys advice, thanks.

    i always set all speakers to small. i set the cutoff freq to 80 hz. now i will crank the subwoofer cutoff freq to full.

    anything else that i should do?
     
  10. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
    Felix, a crossover is not a brick wall. It just attenuates the signal below that point at a slope determined by the order of the crossover. So if the speaker does not have usable output below the crossover point, when the sound produced by the bookshelf (recieves the highpass portion of the crossover network which attenuates the frequencies lower than 80hz) and the subwoofer (receives the low pass portion of the crossover network which attneuates the frequencies higher than 80hz) are summed, the result won't be flat. The sub needs to be capable of flat output above 80hz (preferrably an octave, so to 160hz) and the bookshelf below 80hz (again an octave so to 40hz) in order for the two sound sources to sum flat.

    Dolby Digital and DTS have 5 full range channels and one limited range channel (the LFE or low frequency effects channel). The 5 full range channels have info from somewhere below 20hz up to 20khz. The LFE channel only has info from somewhere under 20hz up to 120hz. If you set all your speakers to large, then the sub will only recieve the LFE info from the DVD. When you set all your channels to small, the sub gets the LFE info again, plus all the info from the other 5 channels that is below 80hz.
     
  11. JohnDG

    JohnDG Stunt Coordinator

    Joined:
    Jul 15, 2000
    Messages:
    238
    Likes Received:
    0
    Trophy Points:
    0
    FYI: I've been working with the PDR-10, 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.
    jdg
     
  12. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    one thing that i noticed was that if i turned the sub cutoff freq to max, the bass would become really, really boomy. i turned it down to a half, and it sounded much better.

    now is there any frequency lost? the logic is this : the satellites could do 60 hz at the lowest. crossover is set on 80 hz. sub is set to 100 hz max. now, everything is overlapped. i think i dont lose any frequency this way.

    so, dustin, this overlapping might cause a big bump on freq chart?
     
  13. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
    Well, this forced my to dig the PDR10 I have, that I'm trying to sell, out of its' box. Kinda glad I did though now, really makes me appreciate just how much better my Tempest is than the PDR-10. So I setup the PDR10 and calibrated it with Avia (was at -2 on my Onkyo with the gain on the PDR10 set to the first black line past dead center). Then I ran the left channel 200hz - 20hz frequency sweep a bunch of times measuring at my listening position with my spl meter with the low pass filter on the sub set at 150hz and some where between 90-100hz. This way of measuring isn't very accurate, but I don't have any proper measuring equipment yet so this is the best I could do. Anyways, I observed no difference between the two on my spl meter.

    Then I put in my current favorite cd for testing out subs sound quality. Kodo's Tataku. Lots of fast low drum work that is really well recorded. I listened to the opening 2 min of track 5 several times switching the crossover between wide open and 90-100hz as well as the 3:20-4:00 min mark. I did notice a very subtle difference between the two. It seemed to me there was something missing in the bass drum hits with the crossover set at 90-100hz that was there with the crossover wide open. When I set the crossover to below 70hz the difference was no longer subtle, there was definately something missing.

    Another thing to keep in mind is that just because you have the gain on the sub's amp set to 1/2 way doesn't mean you can't use all the power the amp can put out. The gain knob isn't a magic stop point where if you set it to 1/2 you can only get 50 watts out of the amp. It is just another regulator of the line level voltage before it is amplified. If the input signal is high enough, even with the sub's gain set at 1/2 it is still possible to use all 100W the amp is capable of.

    The one time I went to switch the crossover setting I accidentally cranked the gain instead of the crossover. Sat down, started the track, holy crap, what happened, this is boomy god aweful bass. So I played with the gain setting combinations a little bit. Even if I brought the level back down to a calibrated one with the receiver, the bass was still really boomy if the gain was set much past 3/4.

    So what worked best for me was to keep the crossover cranked, keep the subs gain below 3/4 and calibrate it with an spl meter and a calibration disk.
     
  14. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    dustin, thank you very much for doing so much work just to answer my silly question.

    but, please, can you please summarize all that? i dont understand the terms.

    explain me these sentences :

    "left channel 200hz - 20hz "

    "low pass filter on the sub set at 150hz and some where between 90-100hz"

    "crossover wide open"

    "The gain knob isn't a magic stop point where if you set it to 1/2 you can only get 50 watts out of the amp"

    "sub's amp "


    but i do understand this :
    "So what worked best for me was to keep the crossover cranked, keep the subs gain below 3/4 and calibrate it with an spl meter and a calibration disk. "

    i will follow that advice, thanks a bunch.
     
  15. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
     
  16. Charles M Berry

    Charles M Berry Stunt Coordinator

    Joined:
    May 6, 2002
    Messages:
    129
    Likes Received:
    0
    Trophy Points:
    0
     
  17. felix_suwarno

    felix_suwarno Screenwriter

    Joined:
    Dec 2, 2001
    Messages:
    1,523
    Likes Received:
    0
    Trophy Points:
    0
    dustin, thanks.

    charles...thank you for sharing that. i thought there was something wrong with my subwoofer. dont get me wrong, i really like pdr10 now. what do you expect, i live in an apartment. it sounds much tighter...too bad i dont have the spl meter. it costs 40 bucks! i had better spend the money on something else at this point.
     
  18. Dustin B

    Dustin B Producer

    Joined:
    Mar 10, 2001
    Messages:
    3,126
    Likes Received:
    0
    Trophy Points:
    0
    Charles, are all your speakers set to small?

    If the low pass filter is set in the 100-125hz range it will have absolutely no effect on test tones below 80hz. It can only affect frequencies above 100hz. In the case of the LFE channel you will then be attenuating something that should not be attenuated. If your other speakers are set to small you will have the low pass filter of your receiver starting to attenuate the signal at 80, 90 or 100hz (depending on your receiver) and then the sub will start filtering this already filtered signal (in other words cascading).

    The only explanation I can see for this sounding better to you is if your room has some modes that boost output in the 100-160hz range. Then setting the crossover here should lower their levels taming the room interaction.

    I pulled mine out and tried to observe what you guys are talking about. I couldn't measure it and what I heard wasn't an improvement. So it has to be either room interaction, or something is wrong with your subs (or I could have gotten lucky and mines the anomolly, but in a good way).
     
  19. Robert_Z

    Robert_Z Screenwriter

    Joined:
    Jun 16, 2002
    Messages:
    1,017
    Likes Received:
    0
    Trophy Points:
    0
    I own a PDR 12 and have noticed similar results. Setting the sub cutoff frequency to 150 results in horribly bad sound. Absolutely no oomph to the bass. My Yamaha receiver has its crossover set at 90. I set my PDR 12 to 90 and have the sub volume set at 50%. I found these settings to provide the most slam. I never did set the volume past 50%. Don't want to blow the sub.
     
  20. JohnDG

    JohnDG Stunt Coordinator

    Joined:
    Jul 15, 2000
    Messages:
    238
    Likes Received:
    0
    Trophy Points:
    0
    Dustin,

    I did pretty much the same with with the Avia sweeps and all.

    However, what I found was that -- to get the same db's at the low Hz (below 60Hz) levels after turning down the crossover on the PDR10 -- that I had to turn UP the sub's volume knob to compensate (from 50% to 60%).

    The net affect was flat db's from 80Hz down to 25Hz at levels less than 95db's on the SPL meter. Paired with Monitor 7's, I have a flat frequency response line from 120Hz down to 25 Hz, with the exception of the (room induced) boom in the 40's. This is using a 80Hz crossover on the receiver.

    jdg
     

Share This Page