Are you guys sound junky purists who use no tone control? I’m a low brow stereo aficionado and use a heavy dose of bottom and top EQ and my A7’s play plenty low, although I have to adjust for every different song and volume change and they sound great whether playing classical, jazz, fussion, or rock. Or play them flat and just stand 100 feet away and then they have all the bass you could ever want.
Last edited by VolvoHeretic; September 10th, 2011 at 11:48 PM.
My first amp bought in 1974 or 5 (a Sansui au-6500) had tone controls and i used them. I sold it in 1980 and havent had an amp with tone controls since. They fell out of grace with most manufacturers as well as the DIY crowd.Originally Posted by VolvoHeretic
Regards
Kjartan
My amps don't have tone controls either, but I have a $60 Radio Shack 15 band EQ which works and sounds amazing and loss in fidelity purity is more than made up with tonality equality(are those even words?).
Last edited by VolvoHeretic; September 11th, 2011 at 12:25 AM.
Yeah, long, boring story about design cut short, moving the vent to the extreme bottom will cure these problems for most folks, though some [like me] need to additionally critically damp the vent to get a fast transients 'sealed with extra gain' response.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
I don't have my notes available, so don't recall 620's exact tuning, etc., but it should do 40 Hz solidly. To go lower requires either a larger cab tuned lower or a lower vent tuning and corner loading for the 620.
Even leaks around screws can ruin a reflex's tuning, causing a much higher F3, Fb.
Regardless, once you're sure there's no leaks, Jeff's XO has an adjustable HF shelving pot same as the OEM unit, so as it is dialed up, the tonal balance shifts to an increasingly mid-bass heavy one and if you don't like what it does to the extreme HF you can experiment with higher/lower by-pass cap values [c4].
WRT weak magnet testing, I know of no way for the casual DIYer to test them, but the dead giveaway is that it increases the driver's Qts a lot, meaning you'd be here complaining about having a 'fat'/'slow'/'boom' bass due to the 620 being too small and too high tuned for them without plugging up the vent and even then it maybe too small.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Not me, once I learned about such things, I've always used some form of response shaping EQ, especially CD horn EQ, and back when dbx first offered a digital RTA/EQ with the ability to save multiple response curves one could choose from its remote 'on the fly', I gladly paid a full month's salary for it, which at the time was quite a 'stretch' for me financially.
It lasted around 25 yrs of ~daily use, so got my money's worth, but its many generations newer replacement is way more than my retirement budget can recover from in these trying economic times.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
Thanks for all the good suggestions. Work has been disturbing my hobbies the last couple of days
I haven't had the time to dismount the speakers, take pictures of the membranes and remove some of the fiberglass so I only have top, side and back covered.
I have however been playing with the shelving pot in the JM filters and it does not have a huge effect, everything is a little more up front on the one extreme setting and a little slower/darker on the other extreme. I use the middle position for most of my listening.
If removing damping from the cabinets is not enough i might try closing the front port and cutting a port on the bottom (I have the 620's mounted on wheels so my wife can move them around) and see what that does.
Regardless of the missing bass output, the Altec's still sound quite good and are smooth, detailed and fast.
Regards
Kjartan
Bill H. at GPA told me a while back that loos of magnetism led to a loss in the mid freq's., not the low end.
If I may chime in on recones, I had a 604c done by GPA a few years ago and with no disrespect the new suspension was very stiff, and whether or not related there was less bass than in an unreconed version I had around.
I ended up getting another original 604C and mended any tears and brittle areas of the cone with layers of tissue paper interspersed with and made rigid by diluted white glue, then painted. Doesn't look so slick but sounds a charm.
Intresting, if my 604s have recently been reconed (they look new), bass shyness may be a break in issue. My lowthers took at least 2years break in to be tolerable on most music and continued improving over 10+ years.
Regards
Kjartan
Just removed the Altecs 604s and removed som fiberglass from 2 sides in each speaker. Initial impression: more open/transparent or lively sound. The bass membranes are stamped 1803035662 and 1803035(5or6) cannot se last two figures.
Does this indicate original membranes or later recones?
Regards
Kjartan
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