Anyone else own Altec 604's?

[Dylanl]

I just purchased a set of Altec 604's in an Onken style cabinet. These speakers sound so differnt than any others I have heard. My reference speaker would be the Altec Model 19. Just wondering if anyone else has listened to these and what was your 1st impression when you did.

I am running these without a crossover just a 6.2 cap from the woofer to the horn.

Hopefully your replies will macth my findings.

[scott fitlin]

Ive never owned any 604,s but have heard them in studios many times.

To me, they have some of the best imaging, and coherent sound.

[moldyoldy]

.....snip......I am running these without a crossover just a 6.2 cap from the woofer to the horn.

Hopefully your replies will macth my findings.

If your findings tell you they sound like crap, you'd be right. Get some (correct) crossovers on them! I can think of few systems more critical of the right XO than a duplex. As it is, if they're 8 ohm, the cone's running fullrange, and is very capable of going way higher than the WL size of the horn in front of it, which simultaneously is going to be unloading from the 6dB slope from ~ 3200Hz. Polars will look like daisy petals. If they're 16 ohms, you've probably lost a 'fram by now.

604s are stretching on both ends to properly meet in the middle as it is, but with the right XO, cabinets, and location can be hard to beat. Don't expect quite as much bass as 19s provide (read-flatter response), and you should be very pleased when you get them setup right. I hear GPA now sells new XOs for all versions of 604s.

[Dylanl]

I know others that have run 604's this way and multiple peolpe said that this would be fine to start with. I have not had any functioning problems. I am driving them with tube amps and a 5ar4 recitfier tube that is slow comming on.

Fram what do you mean by that? Also these are 160hms

[moldyoldy]

Perhaps you misunderstood someone's description of 604s in a biamped setup, where only a capacitor is used on the HF driver for thump protection. However, in such a system, a crossover is still used, but is a different type that's connected before two separate power amps, one for the cone, and one for the HF driver.

The tiny horn in a 604 has a sharp low cutoff around 1500Hz which varies slightly between models that used different horns. Below this, the horn no longer presents a load to the diaphragm (fram), allowing over-excursion which can ruin it. Stock XOs are 2nd order Butterworths with an XO point designed specifically for the horn in that particular model, so a 604A will be somewhat different from a 604E, G, etc. You need 16 ohm XOs, 8 ohm won't work.

There's way more to it than I have patience to describe. I'm not trying to diss either you or your speakers, merely emphasise the importance of the crossover, and perhaps save you a $120 'fram or two. Trust me, your 604s will perform nowhere near as designed (not even close) until you have appropriate crossovers connected correctly, or the equivalent in a biamp setup.

[Dylanl]

I know the difference betwwen active and passive. This is the simplest crossover 1st order.

Since there are som many differnt crossovers for this speaker which one is best?

[spkrman57]

That would be a 604-8K with modern revisions by Great Plains!

Ron

[scott fitlin]

That would be a 604-8K with modern revisions by Great Plains!

Ron

Ill second this. You get factory fresh crossovers, nice, new caps.

Well made, and built for your speakers!

[moldyoldy]

C'mon guys, you're slipping! He's got 16 ohm 604s!

Actually, a single cap is merely a high-pass filter. Without a corresponding low-pass filter included, it can't really be called a crossover.

As to which XO to select, ideally it should be the one designed for whatever model you have, for example, if your drivers are 604-16Es, a 604-16E XO would be ideal. Unfortuneately, used ones are pretty pricey lately. Ron's suggestion of new ones from GPA would be my choice as well, (only you need 16 ohm models instead of the 8 ohm ones he mentioned). If you go this route, just tell Bill your exact speaker model # when ordering. I don't know the price, but they're likely cheaper than some used ones go for on eBay, and no question as to the quality.

Your 604s being 16 ohm limits other more generic commercial choices, none of the online stores I checked had any that would work, lots of 8s, no 16s. DIY appears to be the only really cheap alternative.

[scott fitlin]

Yes, tell Bill at GPA the model number, they will make the XO suitable for the impedance of your drivers!

This is important.

And, with proper XO, youll get the best your 604,s have to offer, no doubt.

[Dylanl]

Are there any plans that I could follow to build my own crossovers?

[spkrman57]

I don't have the website right now...check a search on audio.asylum for Jeff Markart(sp???) on the high efficiency section to find links to the Altec forum.

He has several according to the different model 604's!

Hope this helps!

Ron

[Dylanl]

Thank You.

Just one more question would a pair of Altec 605B crossovers work 16ohms crossed at 16,000 hz?

[spkrman57]

604 = 515/802
605 = 416/806

Roughly 2db difference between the two.

[moldyoldy]

From your post on Hostboard, I learned your 604s are either Cs or Ds, which crossed at 1600 (not 16000) Hz, and used the Altec N1600 16 ohm crossover. The N1600 is also the XO listed for the 605A and the 16 ohm 605B, so IF the crossover in question is a 16 ohm Altec N1600, the answer would be yes.