CompuServe Thread

#Soundblaster/CdRom

11 messages in this thread
#28089From: Michael R. JonesOct 5, 1992 6:28 PM
I have a SoundBlaster card for my PC running under Windows 3.1 and Norton Desktop 2.0. The card runs well, and the attached speakers add the appropriate sounds under Windows or DOS SoundBlaster games. I've just added a Sony CdRom drive, and it is now functional. US Atals, World Atlas, etc all work well. One problem though is the CdRom sound output. If I plug the speakers directly into the CdRom headphone jack, the sound works ok. But if I plug a cable into the CdRom Phono-Plug output jacks, then into the SoundBlaster "Input" jack, the speakers don't work. Maybe a splitter connector would work, where the speaker plug and CdRom plug are both connected to the SoundBlaster output plug. Would this work, or is another solution better?
#28102From: Clarke FerberOct 5, 1992 9:23 PM
Michael, if I make a suggestion. Call Creative Labs and buy the audio cable that runs from their CD-ROM to the PRO ($6). Also buy a power cable that converts from the normal size to the size for the 3.5" floppy drives. You will find the smaller connect on the power cable fits very nicely in the audio out of the CD-ROM. Cut the big end off of the power cable. Cut the end off of the SBPro audio cable that DOES NOT plug into the pro (the end for the SBPro CD-ROM, which does'nt fit into the SONY). Connect the two together (solder or use crimp connectors). The red wire from the SBPro cable is the right channel, the white is left. The pins on the CD-ROM are labeled. I have done this for my SONY and it works great! Plus I can control the CD volume from the SBP Mixer. -Clarke
#28131From: Michael R. JonesOct 6, 1992 11:07 AM
Clarke, Thanks for your suggestion, but I think I've already tried this. With my Soundblaster card came a headphone jack to (2) phono plug cable. I have plugged the headphone jack end of the cable into the Soundblaster "input" jack, and the 2 phono plugs into the LEFT/RIGHT audio output jacks on the back of the Sony CdRom drive. No sound results from this link. Could this only work when using the Soundblaster CdRom Player programs? I am trying to get sound from (as an example) the MAMMALS CdRom program, which outputs sound from the CdRom.
#28182From: Clarke FerberOct 7, 1992 5:36 AM
Michael, I did'nt have any luck with that approach erither, my guess is the signal amplitude or impedance is just correct for it to work. But with the method I mentioned it works great! For the last three days, I have been playing CD's at my computer – even though I have 3 other CD players in the house…. Plus this way you get to control the output of your CD-ROM using the SBP-MIXER program. -Clarke
#28237From: Keith E. MyersOct 8, 1992 3:42 PM
Michael, I have the same arrangement as you and all CD's work fine. Your statement about how you're powering the speakers is vague though. Are you driving the speakers from the SB Pro's internal speaker output? Or are you using self-powered speakers and still tapping off the front panel headphone jack? The audio output present at the headphone jack is present at the RCA phono jacks also. Are you sure you're plugged into the correct jack on the SB Pro? The input jack is the second jack down from the top of the bracket. Have you turned up the 'slider' for the internal input in the SB Mixer program? Do you have a SB-SET statement in your AUTOEXEC.BAT that sets the LINE volume? You should have no problem getting either YELLOW or RED BOOK audio out of the CDROM drive and into the LINE input on the SB Pro. Let me know if these suggestion/questions lead you to success or failure. I'll be glad to help. Keith.
#28565From: Michael R. JonesOct 14, 1992 6:36 PM
Keith, Thanks for your reply, I'll check the items you suggested tonight. A question comes to mind initially though. Lets say that I have the CDROM RCA LEFT/RIGHT jacks wired into the Soundblaster line input jack (2nd from top). Now I play a CdRom program such as MAMMALS, which has CdRom sound. Do I have to run a Soundblaster program BEFORE the Mammals program to enable the SOundblaster card to pass the CdRom Input signals through the card into my external speakers (which are attached to the Soundblaster output line)? Or will only programs which make specific calls to the SOundblaster card provide sound in this hardware configuration?
#28577From: Clarke FerberOct 14, 1992 9:46 PM
Michael, first of all you would'nt want to connect your CD-ROM audio out to the SBPro through the line-in jack. The impedance is totally incorrect for good audio. Connect the CD-ROM audio out to the CD-ROM in on the card. You can get a cable from creative labs for $6. That way you get the correct input impedance, plus you can use the mixer/SB-SET to set line levels. Your line settings may have to be set the first time you install the card. After that you don't need to do anything for you to get audio out from the CD-ROM. -Clarke
#28670From: Michael R. JonesOct 16, 1992 11:59 AM
My Soundblaster card is not the 'Pro' model, and there is no CDROM Input In Jack. Is this just available on the SOundblaster Pro?
#28675From: Keith E. MyersOct 16, 1992 12:51 PM
Clarke, I would like to know on what basis is your claim of incorrect impedance of the Line-In jack for CDROM audio is made. I don't see any specific specifications of impedances for any of the inputs on the SB Pro except for a text mention that the microphone should be a low impedance 600 ohm type. I would assume that use of the Line-In nomenclature leads one to assume the industry standard impedance of 47K ohms. This matches perfectly the Line-Out impedance of the Sony CDROM. Your statement about using the mixer/SB-SET with a CDROM connected to the stake header on the card implies that the mixer/SB-SET is not functional with CD audio inputted into the Line-In jack. This is patently untrue. The mixer/SB-SET functions are fully implemented for the Line-In jack, else why have a dedicated slider for the Line-In input. Finally, for users of external CDROM units such as I have, the Line-in jack is the only way to get audio into the SB Pro without hacking a hole in the back of the PC's case in order to get your proprietary CD connect cable to the SB Pro card. Looking forward to your further reasonings. Cheers, Keith.
#28583From: Keith E. MyersOct 15, 1992 12:28 AM
Hi Michael, OK let's see if we can get the hardware aspect of this dilemma out of the way. I do believe if I remember right that the Mammals disk has both Yellow and Red Book audio. Red book audio is nothing more than digitally recorded audio that has been converted back to analog _onboard_ the CDROM drive and passed to either the headphone jacks and/or the RCA phono jacks on the back of the CDROM. If Red book audio is plugged into the LINE input on the SB Pro, it's just like plugging an input from an audio CD player into the LINE input of a stereo amplifier. The SB Pro acts as nothing more than an amplifier passing the amplified audio onto the external speakers. Yellow book audio OTOH is the digital representation of audio in a message packet kind of way. It's sort of like MIDI, there are just commands to a sound device to reproduce the required sound via the DAC's (Digital to Analog Converters). In the case of the CDROM the signals for the audio pass over the SCSI cable to the CDROM interface card as digital signals. I must say here, I cannot remember if you have a Sony CDROM with its proprietary interface or an industry standard SCSI interface. Once the Yellow book audio signals are decoded by the SB Pro, they are passed out of the OUTPUT jacks as normal amplified analog audio on to your external speakers. So the only difference between RED and YELLOW book audio is where the digital to analog conversion takes place. Anyway, sorry for the long dissertation, back to the question: >Do I have to run a Soundblaster program BEFORE the Mammals program to enable >the Soundblaster card to pass the CDROM input signals through the card into >my external speakers (which are attached to the Soundblaster output line)? The only SoundBlaster program you need to run is the SB-SET program, usually as a statement in your AUTOEXEC.BAT file. This sets the various input [>> Continued in next msg]
#28584From: Keith E. MyersOct 15, 1992 12:28 AM
[>> Continued from previous msg] levels on the SB Pro to accept whatever inputs you have plugged in the card. The important ones for your case are the Master and Line inputs. Legal values ar 0-15. Let me reinforce the fact that this program is not necessarily _allowing_ the Mammals audio to pass through to the SB Pro, its just setting an amplification level so that the sound is audible. You should also define an environment variable that helps point the way to the SB Pro directory that contains the SB-SET program or any other of the SB Pro utilities that came with the card like SB TALKER and such. An example from my AUTOEXEC.BAT follows: SET SOUND=D:\SBPRO SBP-SET /M:12,12 /VOC:15,15 /FM:15,15 /LINE:15,15 /X:07 The info on these statements is in the SB Pro manual. I suggest you try adding statements like the one above, modified of course to match the directory where you have the SB Pro software installed. Another way of controlling the SB Pro's inputs is via the Windows based SB Mixer utility program that comes with the SB Pro. Make sure you have the sliders for the Master volume turned up, plus the sliders for FM sound and the Line input. Well I hope that I have given you some ideas to try out. Let me know if you get the CD audio to work through the SB. Cheers, Keith.