Subject: Re: attenuator - response summary From: =?ISO-8859-2?Q?Pawe=B3_Ku=B6mierek?= <pawel.kusmierek@xxxxxxxx> Date: Mon, 9 Jan 2012 21:15:36 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--0015174024e80f336404b6231949 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hello, a follow-up to my questions about attenuators: here is a device I was made aware of recently: http://www.ced.co.uk/usa/2pl06y.shtml (click on CED 3505). I regard software and hardware from CED very highly, but I was wondering if any list member has had experience with this particular device= ? Thanks, Pawel 2011/11/20 Pawe=C5=82 Ku=C5=9Bmierek <pawel.kusmierek@xxxxxxxx> > Hello everyone, > > thanks to everyone who replied to my question about attenuators. > > Some responses were off-list, and some were "off-off-list" (I asked > elsewhere), so here is the summary. > > To remind you, I was looking for a "commercially available precise > digitally controlled (i.e., repeatable) attenuator with fast and quiet > attenuation changing. Preferably, but not necessarily controlled via RS23= 2." > The RS232 was suggested because I want it to be controlled from CED > Spike2/Power1401 system or from NBS Presentation, or from similar systems= , > and RS232 looked like a sensible (although pretty old) solution. > > Basically there were two suggestions. > > 1. TDT PA2 > > advantages: > - wide attenuation range of ~120 dB (0 to - 120dB), > - small gain step (0.1 dB), > - high accuracy (0.05 dB), > - good noise/distortion figures > - manual control possible > - attenuation value is displayed > - ready to use > > disadvantages: > - price: $725 for a single channel device, but additional > control/power/PCI cards, etc. hardware and software are needed, which > drives the price of a single-channel attenuator to ~$2,500. I think that > the second channel can be added for additional $725 only, but still it is > not cheap > - control: via an AciveX control, I am not exactly sure if (and how) I > could do this from CED or NBS systems. > > A person suggested TDT RX5 and I was not able to find what it is. However= , > RX6 and RX7 appear to be powerful DSP devices, so RX5 is probably too muc= h > capability-wise and price-wise than I need. Please correct me if I am wro= ng > here. > > > 2. A "digital potentiometer" chip. Specific models suggested were Dallas > Semiconductors DS1801, Cirrus CS3310 (or 3308 for 8 channels) and Texas > Instruments PGA2320. > advantages: > - low price - the chip itself is in $5-$20 range, for a 2-channel device > - wide attenuation range ~127 dB for the CS and PGA (~63 dB for the DS) > - pretty small gain step/accuracy (CS: 0.5/0.05 dB, PGA 0.5/0.1 dB, DS > 1/not sure) > - good noise/distortion figures > - control via three serial TTL lines (more may be needed if certain > features cannot be set to enabled or disabled permanently) - this could b= e > achieved from NBS Presentation via LPT printer port or NI I/O board, and > from CED Spike2 via the 1401 interface > - zero-crossing mode - the chips may be set to attempt to change > atttenuation on analog zero-crossing to reduce artifacts > > disadvantages: > - a device has to be built around the chip - power supply (PGA: +5V, +15V= , > -15V, CS: +/- 5V, DS: +3 or + 5V), connectors, possibly buffers. This wil= l > increase the total price, but definitely it will be still well below TDT > PA5 price, even with labor factored in. > - for CS and PGA the 127-dB attenuation range is NOT 0 to -127dB, it is > +31.5dB to - 95.5dB, which may have clipping implications > - no manual control and no way to read back the set value (unless special > steps are taken) > > One person warned me that "digtal audio attenuators" typically do not hav= e > 1 dB steps, but fine steps at high levels and coarser steps at lowe level= s. > However, the chips that were suggested to me have 0.5 or 1 dB steps over > their attenuation range. > He also proposed using and old SoundBlaster SB16 or AWE32 as an > attenuator. These cards need a computer with ISA bus, which are not > available for me (and frankly, I doubt there are many operational machine= s > from these days around). > > > Thanks again to everyone for your suggestions, > > Pawel > > > ** > * > > * --0015174024e80f336404b6231949 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable <div>Hello,</div><div>=C2=A0</div><div>a follow-up to my questions about at= tenuators: here is a device I was made aware of recently: <a href=3D"http:/= /www.ced.co.uk/usa/2pl06y.shtml">http://www.ced.co.uk/usa/2pl06y.shtml</a>= =C2=A0(click on CED 3505). I regard software and hardware from CED very hig= hly, but I was wondering if any list member has had experience with this pa= rticular device?</div> <div>=C2=A0</div><div>Thanks,</div><div>=C2=A0</div><div>Pawel</div><div><b= r><br>=C2=A0</div><div class=3D"gmail_quote">2011/11/20 Pawe=C5=82 Ku=C5=9B= mierek <span dir=3D"ltr"><<a href=3D"mailto:pawel.kusmierek@xxxxxxxx">p= awel.kusmierek@xxxxxxxx</a>></span><br> <blockquote style=3D"margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-= color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class= =3D"gmail_quote"><div>Hello everyone,</div><div>=C2=A0</div><div>thanks to = everyone who replied to my question about attenuators.</div> <div>=C2=A0</div><div>Some responses were off-list, and some were "off= -off-list" (I asked elsewhere), so here is the summary.</div> <div>=C2=A0</div><div>To remind you, I was looking for a "commercially= available precise digitally controlled=C2=A0(i.e., repeatable) attenuator = with fast and quiet attenuation changing. Preferably, but not necessarily c= ontrolled via RS232."</div> <div>The RS232 was suggested because I want it to be controlled from CED Sp= ike2/Power1401 system or from NBS Presentation, or from similar systems, an= d RS232 looked like a sensible (although pretty old) solution.</div><div> =C2=A0</div><div>Basically there were two suggestions.</div><div>=C2=A0</di= v><div>1. TDT PA2</div><div>=C2=A0</div><div>advantages:</div><div>- wide a= ttenuation range of ~120 dB (0 to - 120dB), </div><div>- small gain step (0= .1 dB), </div> <div>- high accuracy (0.05 dB),</div><div>- good noise/distortion figures</= div><div>- manual control possible</div><div>- attenuation value is display= ed</div><div>- ready to use</div><div>=C2=A0</div><div>disadvantages:=C2=A0= </div> <div>- price: $725 for a single channel device, but additional control/powe= r/PCI cards, etc. hardware and software=C2=A0are needed, which drives the p= rice of a single-channel attenuator to ~$2,500. I think that the second cha= nnel can be added for additional $725 only, but still it is not cheap</div> <div>- control: via an AciveX control, I am not exactly sure if (and how) I= could do this from CED or NBS systems.</div><div>=C2=A0</div><div>A person= suggested TDT RX5 and I was not able to find what it is. However, RX6 and = RX7 appear to be powerful DSP devices, so RX5 is probably too much capabili= ty-wise and price-wise than I need. Please correct me if I am wrong here.</= div> <p>=C2=A0<br>2. A "digital potentiometer" chip. Specific models s= uggested were Dallas Semiconductors DS1801, Cirrus=C2=A0CS3310 (or 3308 for= 8 channels) and Texas Instruments PGA2320. </p><div>advantages:</div><div>= - low price - the chip itself is in $5-$20 range, for a 2-channel device</d= iv> <div>- wide attenuation range ~127 dB for the CS and PGA (~63 dB for the DS= )</div><div>- pretty small gain step/accuracy (CS: 0.5/0.05 dB, PGA 0.5/0.1= dB, DS 1/not sure)</div><div>- good noise/distortion figures</div><div> - control via three serial TTL lines (more may be needed if certain feature= s cannot be set to enabled or disabled permanently) - this could be achieve= d from NBS Presentation via LPT printer port or NI I/O board, and from CED = Spike2 via the 1401 interface</div> <div>- zero-crossing mode - the chips may be set to attempt to change attte= nuation on analog zero-crossing to reduce artifacts</div><div>=C2=A0</div><= div>disadvantages:</div><div>- a device has to be built around the chip - p= ower supply (PGA: +5V, +15V, -15V, CS: +/- 5V, DS: +3 or + 5V), connectors,= possibly buffers. This will increase the total price, but definitely it wi= ll be still well below TDT PA5 price, even with labor factored in.<br> - for CS and PGA the 127-dB attenuation range is NOT 0 to -127dB, it is +31= .5dB to - 95.5dB, which may have clipping implications=C2=A0</div><div>- no= manual control and no way to read back the set value (unless special steps= are taken)</div> <div>=C2=A0</div><div>One person warned me that "digtal audio attenuat= ors" typically do not have 1 dB steps, but fine steps at high levels a= nd coarser steps at lowe levels. However,=C2=A0the chips that were suggeste= d to me have 0.5 or 1 dB steps over their attenuation range.</div> <div>He also proposed using and old SoundBlaster SB16 or AWE32 as an attenu= ator. These cards need a computer with ISA bus, which are not available for= me (and frankly, I doubt there are many operational machines from these da= ys around).</div> <div>=C2=A0</div><div>=C2=A0</div><div>Thanks again to=C2=A0everyone for yo= ur suggestions,</div><div>=C2=A0</div><div>Pawel<br>=C2=A0<br>=C2=A0<br>=C2= =A0<b><font size=3D"5" face=3D"Arial"><font size=3D"5" face=3D"Arial"></fon= t></font></b></div><b><font size=3D"5" face=3D"Arial"><font size=3D"5" face= =3D"Arial"><div> =C2=A0</div></font></font></b><font size=3D"5" face=3D"Arial"><font size=3D= "5" face=3D"Arial"></font></font> </blockquote></div><br> --0015174024e80f336404b6231949--