wind30 Posted January 7, 2005 Posted January 7, 2005 as I tell my boss, nothing is 100% :) ok lar. Then maybe I set the boost at around 6db. go back and fiddle. Why is lower freq boost more damaging?
Lancelot Posted January 7, 2005 Posted January 7, 2005 Why is lower freq boost more damaging? I think it's that deep bass requires lotsa power and driver excursion to drive it, and if you still boost it somemore, might be too much for your sub amp and driver.
wind30 Posted January 7, 2005 Posted January 7, 2005 does anyonw know what to set the "operating level switch" at the back? My sub sounds like 10 db softer after connecting the BFD. is is because I set the operating level switch wrongly?
Jag Posted January 7, 2005 Posted January 7, 2005 In audio, high voltage and high current always comes hand in hand. A 200W amplifier can easily deliver 5A and 40V, depending on reactive impedance to drive our low impedance speakers. One clue is the massive heat sinks in our amplifiers. Because of the high current and voltage, we have to consider both their effects to the driver and the immediate electronics, thus power is usually taken into consideration. After all, thats 5A and 40V passing thru our speakers at full whack. The voice coils in the woofer driver is only converting a small amount of the power to electromotive force, while the rest gets turned to heat. So combining the effects of current and voltage, the alot of power gets dissipated........ as both heat and EMF. So thus power is almost always used in audio considerations. So, while the voltage is merely 2.8x, and current is also 2.8x, the overall effect to consider is ~8x (2.8 squared) *In terms of power, 3 dB = 2x, 10 dB = 10x. In terms of current or voltage: 6 dB = 2x. In terms of perceived loudness: 1 dB is just audible, a 10 dB sound level change represents double or half loudness. Up the gain by 10dB, and voltage is just increased 3x. But power drawn is 10x. So if an amp is already sending 100W to the speaker driver and we up the gain by 10dB, the amp is asked to deliver 1000W of power -> amp will clip into DC and roast the voice coil within seconds
Jag Posted January 7, 2005 Posted January 7, 2005 does anyonw know what to set the "operating level switch" at the back? My sub sounds like 10 db softer after connecting the BFD. is is because I set the operating level switch wrongly? Set it to according the lower of the 2 levels. But a BFD in its optimal PEQ settings will always make a sub softer than before. Since the BFD cuts away the peaks, the overal sub volume will be reduced. I find the best way to splice the sub into the mains to to use warble or spot tones that extends from 200hz to 20hz. Turn off the spl meter and listen to the tone by ear. The 200hz tone should sound just as loud as 150hz, 70hz, 50hz, 40hz and 25hz to our ears. Disregard any SPL meter measurements because the SPL meter mic does not mimic how our ear listens to bass.
wind30 Posted January 7, 2005 Posted January 7, 2005 mm... but mine is like -10db after adding the BFD without doing any EQ....
tsammyc Posted January 7, 2005 Posted January 7, 2005 Sam, use TrueRTA to measure the SPLs. Its a better tool than any SPL meter. Haven't bought an accurate mike yet. May do so this weekend. Also, I thought that since a lot of people have a SPL meter, this would provide a reference for different setups...
tsammyc Posted January 7, 2005 Posted January 7, 2005 The +9 dB at 20Hz EQ setting will only boost the 20Hz component in quieter passages but can never bring the PB-10 louder than 93.9 dB. When it comes to the louder passages, limiting/compression kicks in and the 20Hz recedes into the background... Boosting at normal (not quiet) volumes is exactly what I want. At normal listening volumes, you would not (even in louder passages) be driving the sub near its limit otherwise the other speakers might be producing deafening sound. Hence if you want the Jag twin tower effect agressive house curve (at normal volumes) with the PB-10 you yank up the BFD 20Hz output so it is always producing high output whenever a 20Hz or less frequency appears on the DVD (which is quite rare anyway). Dialog sounds normal since you are at normal volumes, but when a 20Hz passage kicks in the sub immediately jumps to maximum extension giving you that bassy effect which we all call an agressive house curve. You rely on the PB-10's virtually foolproof amp limiter (not compression) to cut down the output if a passage goes so loud that it would damage the PB-10. You are then mostly guaranteed that the PB-10 is kicking out the most 20Hz and under output that it can possibly produce without putting it at risk. One conclusion is that at normal listening volumes you can have an agressive house curve effect with a PB-10. If you like to listen to your DVDs really loud then a more powerful subwoofer like a PC+ tube or PB2 to ensure that the 20Hz tones get sufficiently loud without hitting the amp limiter. The same effect is also gotten by getting another PB-10, which will then extend the headroom at 20Hz
tsammyc Posted January 7, 2005 Posted January 7, 2005 hifi_enthusiast, note that in the Secrets review, Ed Mullen was not able to get the PB-10 to go above 8% THD at 20Hz no matter how high he upped the gain because of the amp limiter. Therefore at 20Hz, he got 93.9dB with 8% THD. With the 2nd PB-10, I hope to be able to get 100dB with 8% THD. I might have some room gain, which will increase SPLs beyond that. Have to wait till tomorrow when I can get the RS SPL meter that I lent someone back.
Phil1624705739 Posted January 7, 2005 Posted January 7, 2005 Some updates guys... I just did some measurements using the SPL w/o the BFD. My REL got a 17dB peak at 50hz while my SVS got a +/- 6dB response from 20hz to 100hz. Look like that position which Jag, Jonlee & me are using is a magic spot! The SVS + C channel response is pretty good too... +/- 9 dB from 20hz to 1Khz mainly flat throughout. Jag, I can't find the excel sheet in the test tone CD.. is there any other software I can use to plot the curve?? Phil
tsammyc Posted January 7, 2005 Posted January 7, 2005 My REL got a 17dB peak at 50hz while my SVS got a +/- 6dB response from 20hz to 100hz. Look like that position which Jag, Jonlee & me are using is a magic spot! Wah. My ears almost spot on man with Hotel California piece. I told you got peak at 40Hz and 60Hz, but my ear brain combination is like 1/3 octave so I guess it was 50Hz. No wonder I ran from your apartment. ;D
Phil1624705739 Posted January 7, 2005 Posted January 7, 2005 Wah. My ears almost spot on man with Hotel California piece. I told you got peak at 40Hz and 60Hz, but my ear brain combination is like 1/3 octave so I guess it was 50Hz. No wonder I ran from your apartment. ;D Hahahhaa... yeah... that was fast man!! Now its a question of whether I want to live with this peak thingee or risk e purity of my stereo path & reconnect to allow the processor & BFD to fool with the audio signal. Phil
Jag Posted January 8, 2005 Posted January 8, 2005 Hahahhaa... yeah... that was fast man!! Now its a question of whether I want to live with this peak thingee or risk e purity of my stereo path & reconnect to allow the processor & BFD to fool with the audio signal. Phil Use this. Its the same excel file thats on the sub cal CD. http://hometown.aol.com.au/MingL00001/Bass_response_by_Jag.xls Some Win XP machines cannot read the CD-extra (bluebook CD). My 2 Win XP machines can't, but Win2k can. ???
Jag Posted January 8, 2005 Posted January 8, 2005 Now its a question of whether I want to live with this peak thingee or risk e purity of my stereo path & reconnect to allow the processor & BFD to fool with the audio signal. Phil Well, without the BFD, your bass is distorted, but audio signal is direct to sub. With the BFD, the bass is not distorted, but audio signal has gone thru the BFD. Since either way, a certain amount of distortion is present with or without BFD. a)Bass peaks of 17dB at 50hz and at other freqs? b)Bass being processed at 24bits/46Khz sampling, but possible to get within +/-3dB? My answer has always been (b). ;D The question is: Which sort of distortion is more tolerable?
hifi_enthusiast Posted January 8, 2005 Posted January 8, 2005 Hahahhaa... yeah... that was fast man!! Now its a question of whether I want to live with this peak thingee or risk e purity of my stereo path & reconnect to allow the processor & BFD to fool with the audio signal. Phil My stereo setup is via DEQ2496, you're welcome to listen :)
Phil1624705739 Posted January 8, 2005 Posted January 8, 2005 I will experiment with option 2 later... Jag, since you are skeptic about the REL... maybe you can drop by to check it out! hehee... Phil
hifi_enthusiast Posted January 8, 2005 Posted January 8, 2005 Boosting at normal (not quiet) volumes is exactly what I want. At normal listening volumes, you would not (even in louder passages) be driving the sub near its limit otherwise the other speakers might be producing deafening sound. Hence if you want the Jag twin tower effect agressive house curve (at normal volumes) with the PB-10 you yank up the BFD 20Hz output so it is always producing high output whenever a 20Hz or less frequency appears on the DVD (which is quite rare anyway). Dialog sounds normal since you are at normal volumes, but when a 20Hz passage kicks in the sub immediately jumps to maximum extension giving you that bassy effect which we all call an agressive house curve. You rely on the PB-10's virtually foolproof amp limiter (not compression) to cut down the output if a passage goes so loud that it would damage the PB-10. You are then mostly guaranteed that the PB-10 is kicking out the most 20Hz and under output that it can possibly produce without putting it at risk. One conclusion is that at normal listening volumes you can have an agressive house curve effect with a PB-10. If you like to listen to your DVDs really loud then a more powerful subwoofer like a PC+ tube or PB2 to ensure that the 20Hz tones get sufficiently loud without hitting the amp limiter. The same effect is also gotten by getting another PB-10, which will then extend the headroom at 20Hz definitely with your dual PB-10s you'll get good levels at 20 Hz... sorry i keep on missing your PB-10 demos, hope to make it to your 'dual PB-10' demo :)
Jag Posted January 8, 2005 Posted January 8, 2005 I will experiment with option 2 later... Jag, since you are skeptic about the REL... maybe you can drop by to check it out! hehee... Phil Can I drop by on Monday after work? Have always been skeptical about the RELs after my experiences with their subs.
Phil1624705739 Posted January 8, 2005 Posted January 8, 2005 Can I drop by on Monday after work? Have always been skeptical about the RELs after my experiences with their subs. Okie.. I will go home early at 6 then... I should be able to reach home by 7. Anyway.. heres e plotted response without BFD. SVS & center only. Because I engage DPL mode which direct all sound to center channel. My stereo bass management got different gain setting. Phil
Jag Posted January 8, 2005 Posted January 8, 2005 How about that peak at 45hz? Can't do anything about that? Phil, I'm available on Yahoo!Messenger...... if you need real-time advise, you can get me there. My handle is "jag_svs".
Phil1624705739 Posted January 8, 2005 Posted January 8, 2005 How about that peak at 45hz? Can't do anything about that? Phil, I'm available on Yahoo!Messenger...... if you need real-time advise, you can get me there. My handle is "jag_svs". These readings are before I setup the BFD. Next up will be to setup the BFD & smoothen the response. Phil
Guest jonlee Posted January 8, 2005 Posted January 8, 2005 swee swee...natural house curve in the making...just need to cut down the 45Hz peak. Okie.. I will go home early at 6 then... I should be able to reach home by 7. Anyway.. heres e plotted response without BFD. SVS & center only. Because I engage DPL mode which direct all sound to center channel. My stereo bass management got different gain setting. Phil
Phil1624705739 Posted January 8, 2005 Posted January 8, 2005 Cough cough... my ears r blowing up man... even after putting on ear muffle... Heres e latest BFDed results.. damn hard to kill some of the peak.. The BFD let inject steriods like that... my sound level in the low end all go up... I didn't boast them much... Phil
Phil1624705739 Posted January 8, 2005 Posted January 8, 2005 Well.. redo all over again for my front & SVS... hows this?? Only added a 4dB boast at 56hz.. the rest all attenuate. Phil
tsammyc Posted January 8, 2005 Posted January 8, 2005 Looking good Phil ;D Looks like you turned the gain up a little and are getting close to 104dB at 18Hz to 20Hz. Betcha been where your REL dare not tread ;) You might be able to push it a little more to test your max SPL Most importantly, how are the movies sounding? Master and Commander? Darla? Keep the reports coming
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