Don Richard

Tubes? Oh yeah, those old things that run hot, burn out, distort, and eat power? I got rid of mine in 1972 or so.

Normally this causes no functional problems. Sometimes a vacuum cleaner will pop the dented cover back. Place the hose end carefully over the dent with the vacuum off, turn it on until cover pops, then turn off before removing hose. Do not jerk hose around when vacuum is running or damage may occur.

Shame on you! You should know better than to play a CD on a decent system! These things are designed for the Ipod generation, FM radio, and autosound. Seriously, the mastering engineers nowdays aren't using the capability of the CD to make a clean, undistorted disc, but to make the loudest disc possible. Heavy compression and limiting, spectral shaping are all used to that end. However, if Death Magnetic is a Warner product there may be hope. Warner sells audiophile remasters at a fair price ($14) and since Metallica is a big seller for them this album may be available that way. We can only hope, but meanwhile thanks for the warning on this poor quality recording.

For 3000 ohm input impedance mixers, 20-25 ft. For 150K ohm tube hi-fi gear about 3 ft. It depends on how much HF rolloff you can stand.

Truly one of the greats. Gonna miss him.

Quad cable has higher capacitance than standard mic cable. In sound reinforcement use quad cables are mostly used for short run mic cables to a stage box. Probably OK for short runs on home equipment. Coax is generally low capacitance and is good for single-ended cables. DIY is the way to go for cables if one has soldering skills. Exact length is good for neatness.

[Y] If your preamp does not have tone controls you could add a graphic EQ to your system. DBX has 15 band per channel and 31 band per channel EQs available for $200 or less. Some folks around here don't like any form of tone control at all but I find that a properly set up and adjusted EQ can improve the sound of nearly any sound reproduction system. In fact, it is difficult to find a professional sound system, or a recording board, that doesn't have EQ. Adding cables that adjust frequency response in a random, uncontrollable way is just plain silly.

I'm running a setup similar to what you want. My crossover does not have a pot that could be used for a volume control, but my CD player (OPPO) does and it is remote controllable. No preamp at all, straight from the CD into the xover.

I recently replaced the foam surrounds on some Boston Acoustics A-150s with the Parts Express kit (10"). The instructions were very clear and the entire job took 3-4 hours for both. Sounds great.

The Aphex Aural Exciter is the distortion box to which you referred, Dave. One can dial in the type and amount of distortion desired. This was, and still is used for multitrack recording and live sound. http://www.aphex.com/204.htm This is the latest incarnation of this box, and one gets the Big Bottom feature also.[:^)]

Could be Forsythe bins by EAW, pics not clear enough. Pretty old stuff.

I have been nothing but satisfied with my OPPO 980 using its analog outputs. Using it as a transport with an outboard DAC further improves performance.

I appreciate your technical knowledge, it's impressive. But if I have to retrain my ears to like something that just doesn't sound as good to me, then all that technical knowledge is of no benefit. My reading of this is that one must get used to listening to a new piece of equipment because it is different than what one is used to.

Generally, 1/4 wave is desirable for most types of speakers. Larger spacings can be successfully used in point source systems that are vertically stacked, depending on the vertical directivity of the elements used. Provided that electronic signal delay is used, time alignment and coherent driver integration can be successfully achieved. Time alignment is difficult to achieve at all points in space and at all frequencies simultaneously, but time alignment will get the arrival times closer than they were everywhere in the room. Tom Danley's Synergy horns are a superb example of modern techniques applied to horn loudspeaker design. And he's using conical horns.

The degree of success in time-aligning a loudspeaker system depends on the crossover frequency and the driver spacing. This is because the lobe null angles should be matched to the polar patterns of the two drivers being crossed, both horizontally and vertically, for coherent summation. If one is crossing a tweeter to a midrange at 6kHz, for example, it is nearly impossible to get time alignment because of the short wavelengths involved. less than 2 1/2 in. The center-to-center distance between the midrange and the tweeter would have to be less than that to get the nulls where they do not interfere with the dominant lobe. This cannot happen unless the mid and tweeter are coaxial, or a unity horn or some other type of summation aperture waveguide are used. This is the big reason that using electronic delay for time-alignment at high frequencies is less than successful. If you move your head just a bit from the alignment point, then the time alignment is off. And this is also the biggest reason that loudspeaker designers try to use the fewest crossover points possible consistent with adequate power handling and output, and why they try to get the crossover point as low as possible. With a lower crossover point the wavelengths are longer, nearly 3 feet at 400 Hz, for example. It is much easier to get the center-to-center distance between the woofer and midrange drivers less than that, so successful time alignment can be achieved and coherent summation can occur. The type A crossover sounds the best to many in terms of frequency response but causes more lobing than a steeper slope crossover would. If they sound good to you, I wouldn't lose any sleep over it.

And it also aims the dominant lobe directly at the position to which the drivers were synchronized.

Time alignment does not involve the spacing between performers, but rather the spacing between the drivers in a loudspeaker system. Whenever there are two or more sources reproducing the same sound anomalies will occur. When the multiple sources are separated in time by more than 10 milliseconds or so, two distinct sounds, as in an echo, will be heard. This is not good. If the sources are separated by less of a time interval a comb filter will result. Comb filters cause a rough frequency response curve and lobing. Lobing causes a rough polar response which results in the sound reflecting off of the walls causing time smear and poor imaging. Irregular frequency response, time smear, and poor imaging. Not what we want. Proper time alignment of the drivers within a loudspeaker system eliminates and/or reduces those problems. The time/level shift between the performers in a recording is what allows us to perceive the stereo effect. A system with bad time alignment between its drivers interferes with that effect, affecting the realism of the reproduction.

They keep getting louder and louder, don't they? Autosound systems with their loudness controls produce more bass with a lower volume knob setting. Same with cheap home stereo systems.

I'm an EE. You are comparing apples to oranges. I was talking about multitrack studios, and in fact that is what was happening in those studios around the time of digital's introduction. You seem to be talking about the recording of orchestras with 2 mics, out of the studio on location. You have explained quite well why those old recordings have the limitations that they do. The tapes from which many vinyl records were made are compressed and gain-ridden just to get it all on tape. A similar process was done at mastering in the pressing facility, to get the recording onto the medium while ensuring adequate playback time. Such compression may be preferred by some. In voice communications work, compression was used to increase intelligibility. That's what had to be done to make it happen with the limited technology that was then available, to bring what you wanted "out of the mud". All of the older recordings suffered from these, and other, limitations. Pressing to vinyl introduced more sonic limitations. Investing lots of $$ in sound equipment to hear noisy, compressed recordings isn't my cup of tea. BTW, I used to have a MagnaCorder (mono, of course) from one of my brother-in-law's radio stations when I was in school. Playing around with it was what lured me away from amateur radio and into sound. Built like a tank, and nearly as heavy.

You have answered your own question by reading the complete statement that I made.

The problem with that is that studios had to spend major money to go digital. As in, replace everything in the recording chain. And at first, results were disappointing. This was with the exact same engineers that made all of those wonderful sounding records on analog equipment. The problem was, and still is, that analog is a more forgiving medium than digital. An engineer can go over 0 dB on an analog recorder and get acceptable results. In fact, that was often used to create a certain sound by some of those engineers. With digital, if one goes over 0 the results are catastrophic. There were other technological obstacles such as the need to synchronize the word clocks on the various pieces of digital gear in the studios. Digital is also a more revealing medium than analog, much like horn loaded loudspeaker systems are. If the mixdown or the mastering engineer does a sloppy job on a digital project, you will hear it and it will sound bad. In spite of the difficulty of working with digital, excellent results have been achieved using that medium. Digital, like it or not, is here to stay. Vinyl will exist only as an audiophile and dance club DJ medium, with the audiophiles ooohing and aaahing whilst listening through the surface noise to pre-digital performances and the clubgoers listening to the DJ scratching and Boom Booming as they writhe in ecstasy. Or is that on ecstasy?

I'm agreeing with you on the subject of great performances. After all, E. Power Biggs quit recording 10 or so years before digital. My objection to vinyl is when the limitations of that medium interferes with my enjoyment of a great performance. As far as being a format cultist, I have much more vinyl than CDs, about 1100 LPs, several dozen 45s, about 150 78s (technically not vinyl). But CDs have spoiled me with their lack of noise and their greater convience.

You keep mentioning dollars and cents. The guys that ran that test weren't selling anything. Such testing doesn't just sound scientific, it is scientifically sound, the state of the art in scientific research techniques. It eliminates the effects of bias and prejudice on the results. Predictably, when the results do not agree with a person's biases and prejudices, that person blasts the results. Pressing vinyl records is about the cheapest, low-tech way to mass-market music. CDs were invented to "have perfect music forever". Relative to vinyl, they succeeded. It's funny how antique car buffs don't go around saying their Model T's are superior to a new Ford, or antique computer buffs aren't saying that their TRS-80s are superior to Dual Core Processor machines. They don't even say that the antiques they own are equivalent to modern equipment. F-16 pilots don't wish they were in a P-47 Thunderbolt when they are sent on a mission. But, in home audio.....

100db dynamic range is achieved with a 1.2 setting on a DBX while at the same time eliminating surface noise on most quality LP's. Wow! Are you suggesting that records are capable of that? Since the mics, mixers, and tape machines used in the vinyl era weren't capable of more than 70dB to begin with, even if the record could do 100dB it wouldn't matter due to the noise generated in the upstream equipment. Even DBX encoded records were limited to 90dB, IIRC. Rumble? I haven't heard TT rumble on anything I've own since my last rim drive Garrard about 1976. Rumble is infrasonic, therefore inaudible. What it does is steal amplifier headroom. The best thing about vinyl is the many good performances, often by deceased artists. The vinyl, in many cases, is superior to even the original master tapes due to tape degradation. Those degraded tapes can be restored to some extent, but with audible consequences. CDs made from such restored tapes will never sound as good as a vinyl pressing made when those tapes were fresh. For recordings made after studios stopped using acetate backed tape things are a bit (no pun intended) different. A well done remastered CD will simply blow away a vinyl pressing. Every time.

The "general public" I referred to were audiophiles and students in a well known recording school. The audiophile group actually did as well (??) as the experienced engineer group. While it is true that the mixing and mastering engineers work at the behest of the producer and must satisfy him, it doesn't mean they don't recognize good sound. It is their job to listen to a project and make it sound like the producer wants it to sound. The importance of the study was not to evaluate mixdown or mastering skills, but to see if anyone could hear any difference when a redbook A/D/A was inserted into an analog playback loop. Very few could.