Simon, thank you for providing this test method.
Would you like to type the formula?
Regards
George
I wonder if the laptop is capable of driving 50' of cable?
A little buffer at the laptop would be an easy experiment to carry out. One channel just to test.
Here are some good eq's.
bpb Freeware Studio: Best Free Parametric Equalizer VST Plugins bedroom producers blog
This is the one that I have been using.
KVR: Christian Budde Noname-EQ - Virtual Effect
I was able to extract and enhance a kick drum click without adding any coloration to the rest of the music with this eq. jer
bpb Freeware Studio: Best Free Parametric Equalizer VST Plugins bedroom producers blog
This is the one that I have been using.
KVR: Christian Budde Noname-EQ - Virtual Effect
I was able to extract and enhance a kick drum click without adding any coloration to the rest of the music with this eq. jer
Well in my case at least, I have a sibilance problem with my speakers if I DON'T put a 2.2 ohm resistor in series with my tweeters 🙂
I did notice that it was worse with my chipamp than it is with my Mosfet amp. RMAA tests of the two amps do show (very slight) differences in the freq response, but not enough, I would have thought, to be able to notice.
Just out of interest (as I saw digital sources mentioned as a possible source of the problem) When I first completed my Chipamp I was having problems with my DVD player, so it was my Analog TV set that I was using as the source, It was listening to voices playing on TV where I noticed the increase in sillibance with the chip amp compared to the mosfet amp.
Attached is a comparison of the frequency response of the two amps (and the frequency response of my sound card as a baseline). It is the swept sine measurement from RMAA 6.2.3
I'd have thought that 0.05 db down at 10Khz and 0.2 db difference at 20Khz would not be enough to be audible, especially since I don't think I can hear past 13Khz these days!
Tony.
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Take a look at my blog - I've got some ideas there about cheap DIY mains filters.
Yes, I was meaning a USB-fed DAC. That could be powered from USB power or it could have an external supply. It would be better than the DAC internal to your laptop in theory because its ground would not be so contaminated with out of band crud. More isolation though might improve the sound further.
After having made the changes in speaker cables and interconnect, I have to say I am definitely having a more musical experience here. Incidentally, the cables I am using now might be as big as 8 gauge, but they are 12' long. I like them a little better than the 6' 12 gauge stranded copper.
There have been a couple of comments here about the length of interconnects. I got an improvement going from 12' to 6'. How can they connect at 50' or 100' with 1V signals? Better op amps will do that?
I was wondering if I shouldn't try something shorter than 6' for an interconnect. Or maybe make a cable for that purpose. I am not running through a pre-amp.
Regarding a flat speaker and sibilance... Actually, the reason why I posted in an amp forum was because I might always talk about this sort of thing in a speaker forum. I get a variation with same speaker and different amplifier. I think this speaker is sensitive to distortion in the very-HF because one can hear it more easily, but what I have started to think is that even when it is not flat, this mangling of the sonics should not be happening.
I think my on-board laptop sound has to be bad. Its too lifeless without SRS, and SRS makes it sound too much better. It seems that logically, because of that, a USB DAC will make it sound better. Maybe so much so that using SRS would not seem like an improvement?
A thought about symbols and vocals...
Would these be complex signals? I think symbols make very complex sounds. It seems like a lot of information accompanies this kind of effect. As I say, bells seem very nice. My symbols and vocals issues are down to an added "silvery and smooth", but not the amount of sibilance that was there before.
Would these be complex signals? I think symbols make very complex sounds. It seems like a lot of information accompanies this kind of effect. As I say, bells seem very nice. My symbols and vocals issues are down to an added "silvery and smooth", but not the amount of sibilance that was there before.
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With computers, the sound card is critical.
I use a Creative X-Fi Titanium Fatality Pro for casual listening. With this comp, I run Foobar.
For more serious work, I switch over to my other desktop with an M-Audio Delta 44 running cPlay. All files on FLAC.
I have yet to work with FLAC files. You have an internal card that looks about the price range I was looking at, in the HRT Streamer II ($150). Here's a USB type from Creative...
Creative Sound Blaster X-Fi HD USB Audio System with THX SB1240
The interesting thing about it is it has a phono input for turning into digital right there - that sounds very cool. Creative doesn't seem to have a USB DAC priced the same as your PCI one, but they have other lower priced USB ones.
It also says...
This laptop has an Intel U7300 (=Core2) @ 1.3 GHz, with 4 GB RAM and a nice video subsystem. What spose would happen if I tried the above on my machine?
damping factor with 8 ohms resistor is equal to the driving voltage divided by the voltage across the undriven side! Easy test easy math!
Romex is the 3 solid wire 12 or 14 gage cable they wire house power with. It doesn't conduct RF very well, which is good for having a computer in one room and an analog amp in the other.
Glad the fat wire (8ga) speaker cable sounds even better. Simple low tech solution.
I don't run a band, I don't know exactly how well they run 100' snakes from the mixer to the power amp.But I own a band snake and a band mixer. For band mixers the load is pretty defined, 24 gage twisted pair. As Andrew T said, the varying loads of different speakers makes it hard for a power amp designer to figure out what RLC compensation to use. 24 Ga twisted pair snake cable is pretty standard, so mixer designers can figure out their load compensation pretty well. I'm of the opinion out current capability is directly correllated to damping factor, along with some effect from feedback to increase accuracy of the signal. So if you want to drive a 100' cable, which has a lot of capacitance, for accuracy a high output current op amp is better than a lower current one. Cheap disco mixers use 4558 op amps, which are specified at 2 kohm load, whereas the 4560 op amp Peavey used on my band mixer is specified to 25 ma output current.
It is worth noting the 40 Damping factor ST120 amp has one output transistor pair per channel(2n3055 equiv), whereas the CS800s with damping factor 400 has 4 output transistor pairs per channel (MJ15024 equiv). So more current is available at the speaker terminals with the higher DF amp.
I made my RF hash input filter for the disco mixer by salvaging a 20:20 toroid from a dead PCAT power supply, where it was probably a hash filter. Then I unwound 20 turns, and put those 20 turns on another toroid core I had bought in 1975. One on + one on return power supplies coming into the ferrous mixer case from the 18VDC wall transformer. Voila! no more RF noise from the lamp dimmer at half dim in my speakers.
Glad the fat wire (8ga) speaker cable sounds even better. Simple low tech solution.
I don't run a band, I don't know exactly how well they run 100' snakes from the mixer to the power amp.But I own a band snake and a band mixer. For band mixers the load is pretty defined, 24 gage twisted pair. As Andrew T said, the varying loads of different speakers makes it hard for a power amp designer to figure out what RLC compensation to use. 24 Ga twisted pair snake cable is pretty standard, so mixer designers can figure out their load compensation pretty well. I'm of the opinion out current capability is directly correllated to damping factor, along with some effect from feedback to increase accuracy of the signal. So if you want to drive a 100' cable, which has a lot of capacitance, for accuracy a high output current op amp is better than a lower current one. Cheap disco mixers use 4558 op amps, which are specified at 2 kohm load, whereas the 4560 op amp Peavey used on my band mixer is specified to 25 ma output current.
It is worth noting the 40 Damping factor ST120 amp has one output transistor pair per channel(2n3055 equiv), whereas the CS800s with damping factor 400 has 4 output transistor pairs per channel (MJ15024 equiv). So more current is available at the speaker terminals with the higher DF amp.
I made my RF hash input filter for the disco mixer by salvaging a 20:20 toroid from a dead PCAT power supply, where it was probably a hash filter. Then I unwound 20 turns, and put those 20 turns on another toroid core I had bought in 1975. One on + one on return power supplies coming into the ferrous mixer case from the 18VDC wall transformer. Voila! no more RF noise from the lamp dimmer at half dim in my speakers.
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Let us be clear about the difference between sibilance and boosted treble. An equalizer will flatten a frequency response but not do much on sibilance until you squeeze the life out of everything.
However the resonance need not be in your driver! I have seen a loudspeaker where the grille cloth support had a cavity that was the resonance, packing it with fiberglass reduced the problem. Adding a series resistor sounds like that might be the issue.
When the problem is in your driver this may be improved by a Zobel network across the driver. This is just a resistor and capacitor in series. The idea is to provide a flat impedance to the crossover but it also loads the driver.
Again if you can produce a frequency response plot also look at the phase plot, then if you see lots of phase shift centered around a frequency band that may be an indication of a resonance.
Hi Simon, I'll have to have a look at the FR plot of the tweeter. From memory both FR and phase are very smooth, except for a dip around 5.5K which I'm pretty sure is baffle related. I think in this case it is more one of level matching with the rest of the speaker that requires the 2.2 ohms.
Tony.
Tony.
Matched impedances (often with transformers), balanced cables, and an acceptable level of voltage loss, because pro stuff has drive and gain to spare ... you would never trade off THD or frequency response for gain if you were trying to design a lower-priced version of your standard product, for example. Drive the signal hard and pad (attenuate) the input if necessary.
It might be worth mentioning as well that when you are *creating* the performance you don't need to worry about the same things as you do when you're trying to *accurately re-create* the performance.
Errors in the former are just part of the deal, errors in the latter kill the whole deal.
Markgm, your next steps should be attacking the sound card. See if you can get an ASIO driver for that chip, and look at the options you have for Sample Rate Conversion, perhaps with a different player. Look up best practices for Windows audio, check out the Benchmark site for details; they have a wiki on the subject. Naturally it is mostly concerned with their own DAC but there is none the less very good information there you can use. I'd be more specific but I don't do audio stuff on Windows and things change too fast for me to claim to be up to date there.
You can compare SRC software with this site http://src.infinitewave.ca/
Use one of the better ones as your comparison; eg" iZotrope 64 bit SRC steep, no alias " or " Sox 14.2.0 VHQ Linear Phase ".
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Sibilance is something I always came up with using simple crossovers, even with Zobels fitted. It's just coincidence that I used the same or earlier versions of the Vifa drivers you refer to, since they were common, affordable and great for DIY.
The problems have been with the crossover. Specified book designs often didn't work or were designed for something different or any number of reasons but they were wrong in (as Simon 7000 suggests) not suppressing a resonance, or phase or slope integration error etc, leaving a peak above or valley before the critical HF range. An octave above 2.4kHz is right in trouble, IMHO. PC analysers can showl you the likely problems if you also have a suitable flat or calibrated mic. but a simple preliminary test is to invert your tweeter and see what happens to sibilance. Sure, everything around the crossover point will sound haywire, but likely one important problem will change. Now think why.
BTW, I built this combination in a reflex box 20 years ago. I used the optional fabric domed rather than an aluminium domed tweeter with a similar asymmetric slope crossover type to that which I think you are using. It was sibilant. Swapped for a Vifa D25AG, all was fine. When steeper sloped crossovers were used (2nd/3rd order), several types could be adapted to work acceptably.
Changing just the series resistor has the dual effect of shifting impedance and crossover, an interesting technique if you can otherwise restore the HF SPL. 😉
The problems have been with the crossover. Specified book designs often didn't work or were designed for something different or any number of reasons but they were wrong in (as Simon 7000 suggests) not suppressing a resonance, or phase or slope integration error etc, leaving a peak above or valley before the critical HF range. An octave above 2.4kHz is right in trouble, IMHO. PC analysers can showl you the likely problems if you also have a suitable flat or calibrated mic. but a simple preliminary test is to invert your tweeter and see what happens to sibilance. Sure, everything around the crossover point will sound haywire, but likely one important problem will change. Now think why.
BTW, I built this combination in a reflex box 20 years ago. I used the optional fabric domed rather than an aluminium domed tweeter with a similar asymmetric slope crossover type to that which I think you are using. It was sibilant. Swapped for a Vifa D25AG, all was fine. When steeper sloped crossovers were used (2nd/3rd order), several types could be adapted to work acceptably.
Changing just the series resistor has the dual effect of shifting impedance and crossover, an interesting technique if you can otherwise restore the HF SPL. 😉
How small of a gauge do they use running from the source (for these runs)? I just got some connectors and wanted to experiment with a larger gauge of wire. I've got 18 and 16 I can run from the laptop to the amp. Just curious what that does.
Well, first of all they run impedance-coupled balanced lines which mitigates long cable runs to a large extent. With unbalanced cable the short answer is keep it as short as you can get away with. Having said that, there is often an advantage with a longer interconnect and a shorter speaker cable ... if you have too far to go, compromise somewhere is inevitable.
Secondly, my own preference for interconnects is to go higher gauge rather than lower (thinner versus thicker). As for the long snakes, they typically have a relatively high gauge compared to your 18ga ... 20, 24, 26 ga for example. Once you have enough material to handle the voltage/current demand, and that is not very high with line level, going to a fatter cable in my opinion causes problems best left out of the mix.
If you need to go long distances, and you want to experiment with line-level interconnects, you could try coax instead of twisted. You may have some laying about due to a cable TV installation.
I have not tended to use coax in the past for non-digital domain or non-video use, my standard low-cost unbalanced analog RCA interconnect for everyday use is Mogami Star Quad 2534 (2x to hot, 2x to signal negative, shield connected at signal negative on the input end and floating shield at the output end).
A 1m stereo RCA interconnect made with this cable and Canare F-10's will run you perhaps $25, add $1 per meter after that. You'll have to buy the cable and connectors and make them yourself. Marshall has a deal with Mogami in the US and they make pre-made cables, but I can't comment on how they are because it's easier and cheaper to make them myself. Also, since they're sold at music, not audio stores, the RCA-RCA seem somewhat less common to find in stock.
Canare makes a similar cable that I find not quite as good but very close, certainly acceptable, and half the price of the Mogami.
A "Star-Quad" cable is microphone cable with 4 twisted cables and a copper shield. It is designed for high rejection of EMF and RF noise, minimal capacitance, and like all microphone cables, high flexibility and low handling noise. Both the examples above use a very high quality multistrand OFC copper and (teflon or foamed PE) dielectric around the signal carrying cables. The Mogami uses a served copper shield; the most effective with highest coverage compared to braided and more expensive for the cable manufacturer to add. I am not positive what the Canare cable uses.
For more specific use, I may use a different cable geometry, but building one of the above would give you a result at least equal to, and typically better than, ready-made cables at a store costing up to $50. So, they are always handy to have around; they have excellent handling and are better than any cable you are likely to have included with any gear you buy.
Mogami is the overwhelming choice for sound stage, live, tv and recording studio use for general unbalanced permanent wiring and microphone use worldwide ... if you watch TV, own a live record, view the Olymipcs, go to musicals in a theatre or at a college, Monday Night Football ... maybe even at your church (especially if it's on TV) ... either North America, Japan, Europe ... you're listening to Mogami Star Quad, guaranteed.
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Quote:
Originally Posted by geraldfryjr
I have four configurations
1. phillips PCS 706
2. echo GINA-24
3.creative X-FI ELITE
4.sony PCM-2600 dat on spdif interface
Have you got a preference?
I would have to say the gina-24 tops my list of cards.
As it's intended purpose is professional recording.
It is a 4 in 8 out fullduplex 24 bit card.
I haven't found any abnormalities with this card as of to date.
I got the X-FI ELITE within the first few months of it hitting the streets.
This was my first hands on experience with the 24 bit format.
Once I got used to and learned how to work the control panel I was amazed.
The crystalization feature was amazing.
The expanision of 16 bit to 24 bit brought an incredible detail and in your face sound to common cd's I have never heard before.
But as stated before badly mastered material became an even more anoyence and had to be turned off in order for me to enjoy the material.
I could now clearly hear and make out the words of the vocals when using it.
How do they do that?
I had digtized a casset tape of deep purple's (machine head) using my tascam 103 mastering deck and afterwards did an a A/B comparison between the two.
I found absolutey no difference between the two except for a very very very subtle warmth (boost) to low end.
Considering the original source this was a welcome improvement.
The detail approached that of analog for the first time.
The sony PCM-2600 is what it is, the very best of 16 bit technology from its day.
It is what we used to do all of our final mastering.
The same goes for the phillips pcs 706 card as it had better be for the price.
I had paid $200 for it onsale in december of 2000.
The sony seems a bit smoother (as expected) and slightly warmer sounding than the phillips card.
I have not yet taken the time to try and find out the cause of this.
The only draw back of the phillips card was that it is very cpu power hungery even with it's own onboard processor.
It would ocasionaly tax out and lock up my 350mhz and 500mhz computers of those days.
It is the best sounding card IMO compared to any SB16 series or onboard sound sytems I have listened to,mordern day systems exculded of course.
jer
Originally Posted by geraldfryjr
I have four configurations
1. phillips PCS 706
2. echo GINA-24
3.creative X-FI ELITE
4.sony PCM-2600 dat on spdif interface
Have you got a preference?
I would have to say the gina-24 tops my list of cards.
As it's intended purpose is professional recording.
It is a 4 in 8 out fullduplex 24 bit card.
I haven't found any abnormalities with this card as of to date.
I got the X-FI ELITE within the first few months of it hitting the streets.
This was my first hands on experience with the 24 bit format.
Once I got used to and learned how to work the control panel I was amazed.
The crystalization feature was amazing.
The expanision of 16 bit to 24 bit brought an incredible detail and in your face sound to common cd's I have never heard before.
But as stated before badly mastered material became an even more anoyence and had to be turned off in order for me to enjoy the material.
I could now clearly hear and make out the words of the vocals when using it.
How do they do that?
I had digtized a casset tape of deep purple's (machine head) using my tascam 103 mastering deck and afterwards did an a A/B comparison between the two.
I found absolutey no difference between the two except for a very very very subtle warmth (boost) to low end.
Considering the original source this was a welcome improvement.
The detail approached that of analog for the first time.
The sony PCM-2600 is what it is, the very best of 16 bit technology from its day.
It is what we used to do all of our final mastering.
The same goes for the phillips pcs 706 card as it had better be for the price.
I had paid $200 for it onsale in december of 2000.
The sony seems a bit smoother (as expected) and slightly warmer sounding than the phillips card.
I have not yet taken the time to try and find out the cause of this.
The only draw back of the phillips card was that it is very cpu power hungery even with it's own onboard processor.
It would ocasionaly tax out and lock up my 350mhz and 500mhz computers of those days.
It is the best sounding card IMO compared to any SB16 series or onboard sound sytems I have listened to,mordern day systems exculded of course.
jer
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