Thanks for checking. 
If you try a different source you might be able to determine if it's the meter or your CD player.
If you try a different source you might be able to determine if it's the meter or your CD player.
Pano,
I think I found out my CD player has slowly rising output from 20hz. I generated a sweep tone online from 20hz to 20khz. Then copied it to usb pen drive and played it on cd player with cd player line out to line in of my sound card (Motherboard inbuilt). Here are sample files. One sweep generated and other my recorded. Can you do me a favour and confirm ?
1) These are mp3 files
2) please ignore levels of test and recorded sweep as I didn't bothered to check. Used default settings.
3) Test sweep is stereo. but recorded sweep is mono. I only connected one channel.
4) kindly rename the files by replacing .mp4 with .mp3 after file extension.
Thanks and regards. And thanks once more for these nice tests.
I think I found out my CD player has slowly rising output from 20hz. I generated a sweep tone online from 20hz to 20khz. Then copied it to usb pen drive and played it on cd player with cd player line out to line in of my sound card (Motherboard inbuilt). Here are sample files. One sweep generated and other my recorded. Can you do me a favour and confirm ?
1) These are mp3 files
2) please ignore levels of test and recorded sweep as I didn't bothered to check. Used default settings.
3) Test sweep is stereo. but recorded sweep is mono. I only connected one channel.
4) kindly rename the files by replacing .mp4 with .mp3 after file extension.
Thanks and regards. And thanks once more for these nice tests.
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12" in sealed with 10db low shelf. P-P limiter set to 50V with movies pretty much all is used. 20-25V rms
Havent done pink noise to limiter but could be done without bleeding ears, 10db shelf on bass volts rises quite fast.
Yes, 10dB is a lot - about 3X. Just curious of your voltage measurements were with the -12dBFS tones or something else.
Hiten. Thanks for the measurement sweep. Your player has a 2nd order 100Hz high pass with a Q of 0.7 I don't know why that would be. Have you modified it or is there a software switch for high pass or small speaker? Did you measure directly from the CD output?
Last time i saw it hit it to limiter was movie ad astra which has clipping soundtrack.
But my system aint that power hungry exept those 12" with shelf.
Pano,
I have not modified it. There are no switches. The cd player is generic one (with tiny amplifier built in With speaker out. But I dont use it). Also With USB input. 2 Channel Line out, Optical out, 5.1 line out, All are separate.
I measured directly from the player on Stereo line out. could that be that the company did that on purpose not to load DAC/amplifier/speakers? Most bookshelf would have response falling off around 80/100 hz ? But not this steeply. So the company may have deliberately put them.
I am not prolific music listener but as I mostly switch between vinyl player and cd player I once did wonder why my turntable has more bass. But at that time I thought it must be cartridge.
Where would they have placed those filters. ON DAC section ? Will take a look inside today.
Thanks for your help. 🙂
I have not modified it. There are no switches. The cd player is generic one (with tiny amplifier built in With speaker out. But I dont use it). Also With USB input. 2 Channel Line out, Optical out, 5.1 line out, All are separate.
I measured directly from the player on Stereo line out. could that be that the company did that on purpose not to load DAC/amplifier/speakers? Most bookshelf would have response falling off around 80/100 hz ? But not this steeply. So the company may have deliberately put them.
I am not prolific music listener but as I mostly switch between vinyl player and cd player I once did wonder why my turntable has more bass. But at that time I thought it must be cartridge.
Where would they have placed those filters. ON DAC section ? Will take a look inside today.
Thanks for your help. 🙂
Ok I took a look inside. Nothing much inside. Only two PCBs. one DAC and other PS and tiny amp. DAC section is just around 3x3 inches. Only replaceable part is a 8 pin socket for eFeon EN25f80 chip. The rest parts are so tiny my soldering iron will remove 3 to 4 parts at one go
The Stereo lineout section is directly from PCB. For 5.1 lineout they have taken wires from separate socket surrounded by 4 tiny chips.
I will drop the idea of looking further to mods or high pass filter parts. Will replace this as my source with some good one in future. Lucky for me to have taken this test. 🙂
Best Regards.
The Stereo lineout section is directly from PCB. For 5.1 lineout they have taken wires from separate socket surrounded by 4 tiny chips. I will drop the idea of looking further to mods or high pass filter parts. Will replace this as my source with some good one in future. Lucky for me to have taken this test. 🙂
Best Regards.
Absolutely! The test didn't show you what you wanted to find, but it did show you a significant problem with your CD source. Replacing it is a good idea.
The test didn't show you what you wanted to find, but it did show you a significant problem with your CD source. Replacing it is a good idea.
I've only skimmed the last few posts but a couple of thoughts are that if you are using a meter and not a scope then you should look at the sensitivity of the meter. If it has a low 'ohms/volt' (the load it places on a circuit) and if your line output is AC coupled then the meter may well cause an apparent loss in low frequencies.
The other thought is that if the meter only has for example 500 and 200 volt AC ranges then it is pretty normal to have gross inaccuracies in the readings at low level voltages.
The other thought is that if the meter only has for example 500 and 200 volt AC ranges then it is pretty normal to have gross inaccuracies in the readings at low level voltages.
No worries there Mooly. Hiten made a recording of the line output of his CD player. It's a perfect 2nd order high pass at 100 Hz, Q=0.7 His meter wasn't lying.
Perhaps it was meant to always be used with the subwoofer output.
Perhaps it was meant to always be used with the subwoofer output.
Yes thats correct I think. Though stereo lineout out and 5.1 are separate I think company didnt bothered to have a switch/software to make it proper stereo lineout.
Regards
Regards
As Mooly says, it is sometimes best to use a scope when measuring bandwidth/output from devices. I noticed this when trying to measure the bandwith of my output transformers using a multimeter and frequency generator. Thought it was the output from the frequency generator varying between frequency bands, when it was actually the multimeter's sensitivety changing with frequency. No such problem when using a scope.
Yes, which is the main reason that I chose the frequencies for the test tones. All the VOMs I own showed no significant difference between 50, 60 and 120 Hz.
Hi Pano,
I'm getting ready to finish my horn loaded 3 ways. Did you ever do files for testing mids and tweets to work out how small the mid / tweeter amps could be in an active setup?
Maybe something like a 500Hz signal for mids and a 3k for tweets ?
(hoping I can get away with some sort of affordable class A amps on my mids and tweets)
Thanks,
Rob.
edit: I have a decent fluke meter but will have to check whether it can measure AC at 3khz ?
I'm getting ready to finish my horn loaded 3 ways. Did you ever do files for testing mids and tweets to work out how small the mid / tweeter amps could be in an active setup?
Maybe something like a 500Hz signal for mids and a 3k for tweets ?
(hoping I can get away with some sort of affordable class A amps on my mids and tweets)
Thanks,
Rob.
edit: I have a decent fluke meter but will have to check whether it can measure AC at 3khz ?
Hey Rob. No I never published test signals for mids and highs. The mids are no big deal as they tend to peak about where the bass does. But in music the high frequencies roll off and even the peak values tend to be lower than the mids and bass.
You could base your midrange amplifier needs on the low frequency test tones, the peaks will be the same, but of course adjust for driver sensitivity. Highs are a little trickier, perhaps base them on pink noise, which is actually a little hotter in the top end than music. Let me know the bandwidth of your drivers and I'll see what I can figure out,
You could base your midrange amplifier needs on the low frequency test tones, the peaks will be the same, but of course adjust for driver sensitivity. Highs are a little trickier, perhaps base them on pink noise, which is actually a little hotter in the top end than music. Let me know the bandwidth of your drivers and I'll see what I can figure out,
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