If you were choosing a tweeter as part of an active three way system handling 3 kHz up, which one would you go for? Mid range is rated at 80w, bass 100w. Mustn't be delicate. ;-) -- *When did my wild oats turn to prunes and all bran? Dave Plowman London SW To e-mail, change noise into sound.

Any recommended box design software which will cope with 6th order bandpass enclosures? That is, a woofer with a reflex port in both the front and rear chambers. I can't see much point in them except that you can put it in a cupboard or another room and just have a duct through the wall to let the bass out. -- Eiron.

Just to let people know I've just put up a short page on using a computer to experiment with 'upsampling' using various methods. The page is at http://www.audiomisc.co.uk/software/ARMiniX/Upsampling.html It also gives links to two example programs. One plays audio files on a suitable computer, applying a user-selected upsampling filter. The other generates an x2 upsampled wave file from an...

Who said that KEF crossovers aren't very good? http://jpegbay.com/gallery/003192965-.html#11 No chance of saturated inductors in that crossover. And while you're looking, are those early B139s with rubberized cloth surrounds of any interest to TL builders? Worth putting on ebay? -- Eiron.

I have a pair of Nytech Obelisk CA-102 amplifiers which are showing their age. I thought they were the best I could afford when I bought them in the late 1980s. Are they worth restoring to use (rather than sell)? I don't seem to have been able to find any articles about restoring these particular amps on the internet, although I have noticed some people have had them restored with new caps...

Just to follow on from my post about the crossovers, thought I'd tell you what I've been up to. Bought a total of three LS 5/8 with BBC modified Quad 405s a few months back. This design is post my time at the BBC, so I'd never used a pair for work monitoring - but had been impressed on the occasions I'd heard them. However living with a pair for day to day use is often not the same. Also, on...

Why do Speakon connectors jump from 4 pole to 8 pole? Ie, no 6 pole which is what I need. Especially since the 8 pole is physically bigger. -- *How do they get the deer to cross at that yellow road sign? Dave Plowman London SW To e-mail, change noise into sound.

** This link is to an interview in 1989 with "Ross Walker", son of Peter. In it he talks about Frogs, Americans, Japanese, Germans and Audiophiles. Plus many other mildly hysterical things to do with Quad products. Worth a few minutes....

I've been playing with this active crossover http://sound.westhost.com/project09.htm and have used TL072 which I have lots of. But wondered what would be better - without paying a fortune? -- *Be more or less specific *

Having just listened to a CD that was remastered 37 years after the original recording and which sounded quite good, I wondered how tape ages. Does it deteriorate? If so, is it just a loss of HF which can be compensated for? How about print-through, flaking etc? AFAIK the multi-track masters were used so I guess that individual instruments were tweaked and remixed to taste.

Chris J Dixon wrote: A little late, but I have just come across this 1 hour technical lecture about the engineering aspects of the 2012 Olympics & Paralympics opening & closing ceremonies. It fascinated me, and I guess there are more nerds out there. ;-) http://www.youtube.com/watch?v=S0Z8pCTt1hE There is a time lapse at 04:20

One of the "great's" of audio has just passed away:(... http://www.bbc.co.uk/news/world-us-canada-24075429 -- Tony Sayer

Friend of mine who does a club act singing live to backing tracks uses a domestic centre dialogue speaker as her own foldback of the track. And at the moment drives it with an ancient Quad 50 pro amp - which weighs as much as the speaker. Wondered about fitting a modern 50 watt or so amp to the back of it preferably with a SMPS to save weight and size. Anything on the market at a reasonable...

I have an Ortophon MC SL15 cart that was originally fed via a transformer into a normal pickup input. Since 'rationalising' to a pre-amp with no pickup input, I've fitted a pre-amp to the turntable. It's a design by Stewart Pinkerton who used to post here. I'm pleased with the results. However, the cartridge seems much more prone to hum pickup from external sources. First of all from my PS for...

Anyone come across a tonearm with a single pivot point rather than the normal four pivot gimbal ? I have a Thorens TD160 Mk II on the bench that has come in to have the owner's 'soldered with a hot poker' cartridge connections corrected. It appears not to be the original tonearm that's fitted, which was a standard fully mounted type according to the user and service manuals. This arm is a...

I have an old Pioneer PD-8700 which sticks on certain CDs. Obviously the sensible thing to do is to throw it away and get another from the local charity shop. But it would be amusing to get out the scope and try to align it. It needs a (Sony?) YEDS-7 test CD, which would be very expensive if it were available. Does anyone have any idea what's on the test CD? Is there another which would work...

I'd like an audio only media player capable of playing Apple lossless files, that I can control with an iphone, and plug into the back of a mini hifi system. 1TB storage on or physically attached to the media player - no network storage. Any suggestions? -- Cheers, Rob

One of the Quad 405 amps driving my LS5/8 makes the most enormous 'bang' through the bass unit about once a day. Wondered what it was first time I heard it - thought something very heavy had fallen over. Now I know what it is, it is preceded by low level hum for a few seconds then the bang - I assume a cap discharging. Allegedly, the amps had a full overhaul before I bought them including all new...

I have a Cambridge azur 650T tuner. I have a single coaxial cable that at present feeds from a loft aerial (external is not possible) into the FM input via a coax connector. The DAB has an F type connector. I would like to be able to use both FM and DAB from the single cable. 1. If it is possible, what would be the most effective way of setting this up? 2. Is there an aerial that would...

Can't remember when I last changed the belt on my Thorens 160Super so thought I'd have treat. Purchased an 'Original Thakker' belt and installed it yesterday. I didn't expect there to be any improvement sound wise but powered up to check connections still ok, but then after 20secs or so experienced my EUREKA moment! The sound was so much clearer, vocals had better clarity etc.The last time I...