Adding Super Tweeters to 604s?

[joyspring]

To AL-TEC:

Sorry for being so persnickety ;-) Just an observation on the contradictory drivel I've noticed in the `retro'-audiophile world... but it's not only there, it's also prevalent in the pro recording industry as well :-/

Rather than striking an appropriate balance between art and science, participants in both fields tend to rely heavily on voodoo, nostalgia and marketing.

And that's why frustrated engineers are leaving or have left for other, more sane industries. At least I still record.

Don't get me wrong - Altec/JBL/EV have built quality well-engineered products that still have few modern equivalents but that's because they're founded on solid research and engineering, not because they come from the era of tubes, transformers, vinyl LPs and analog magnetic tape.

All said, I still prefer my Altec 604-8Ks (UREI 811As) and Altec 605As because they still perform well (in criteria important to me, flat response to 20Khz not being among them) with the 20/24-bit, 48/96Khz recording equipment I now use.

To JimD:

My alt monitors (Mackie HR824) are ruler-flat to 20Khz yet my dog doesn't seem to mind ;-)

And let's be diplomatic: most everything in that final octave is `harmonics/overtones' The term `Distortion' is a bit harsh (:

I too believe that the Altec compression drivers are among the best although I must give the nod to TAD/Pioneer for top honors in my subjective opinion.

BobR

[Jim D]

In a perfect world there would be no distortion. Yes, there are a few harmonics up there, very few however. Unfortunately, the distortion harmonics of quite a few signal paths, especially some amplifiers end up in this range. It does not take much of it to cause listener fatigue. A prime example is the THX movie systems. They got the bright idea that they needed very high HF response, even through the movie screen. The amount of boost put upon the HF driver in the upper ranges is huge. I cannot count the number of times I have heard women say the sound from these theatres "hurts my ears". Another prime old example is the output of a 30 watt chrome MacIntosh tube amp. Their vaunted Bifilliar (sp) windings in the output transformer try to make both sides of the waveforms the same, resulting in--- distortion, some very high. This is the kind of distortion products I am talking about. I wish it were other wise. Jim

[AL-TEC]

Hi Jim D and all.
When I listen to the sound in THX theaters, I have not heard any "edgy" sounding highs. This is when the theater sound seems to be working as advertised. I like the theaters that utilyze the Klipsch Cinema speakers, or ones using EV.

I am not afraid to use some kind of EQ for my own listening tastes when listening to music playback in my home. I may, or may not use any EQ adjustments. It is just what suits me, and what source I may be listening to, LP vinyl, VHS tapes, CD's .ect. I usually don't just set it "flat" though, and leave it. I really don't like to just use a power-amp and nothing else in the signal path as some purists do. I know this is the least distortion way to do it, but depending on the sources, it may not be to my tastes.

As for the vintage McIntosh amplifiers MC-30 models circa 1956 to 1962, I have a pair, and they are in perfect shape. I am driving a pair of 16 ohm Altec 605A's with these, and it is sound that I favor right now for music playback. These tube amps do have that special output transformer, but I hear no distortion, just really perfect clear sound, not any "fatigue" problems with these amps! I switch around my equipment often when listening to my music collection. I do hear differences in models,brands and types of amplifiers whether vintage or new. Also many Altec amps I have listened to, tube/solid-state, have different qualities. I would say that one reason I enjoy the old Mac amps is just the fun of hearing how great these sound after all these years. It probably makes a difference as to how the Mac MC-30's fare depending on the Loudspeakers they are driving. It seems the vintage Altecs are a good choice


AL-TEC

[Jim Easley]

Just a note. All "THX" cinemas are equipped with crossovers that boost the high frequency. This is done in order to compensate for screen loss. The system is equalized to the SMPTE ISO 2969 standard curve. Simply stated, the system is tuned flat (+/- 2 dB) from 50 Hz to 2 kHz with a 3 dB per octave rolloff to 10 kHz then rolling off an additional 3 dB per octave. The low end is generally allowed to rolloff with little or no eq. Of course, most of what we hear is dependant upon the original mix of the film. In many cases the films today tend towards "louder is better". Digital tracks have compounded additional problems for theatre presentation. Many of the older THX installed systems were not designed to handle the additional dynamic range of digital. To be truthful, most theatres do not upgrade their sound systems. JBL 4675's and EV 9040's are installed in the majority of commercial THX cinemas. The JBL's used in these systems have titanium h.f. diaphrams and do at times sound a little harsh. The EV's DH1A h.f. driver is smoother but suffers at higher output levels.

[tsotjbn]

Hello:

I just bought the Model 19 which has the 802 8g and it sounds GREAT. I however, maybe due to improper speaker placement etc. I do use a TT, tube pre/amp and noticed that the highs seemed a little rolled off to me, maybe due to my age. I added the $35 Fostex FT17H bullet supertweeter with a cheap Lpad and a 1 uF cap to the + terminal. Seems to add a little sparkle for me but I am definitely NOT a technical type person so YMMV.

Vince