ALTEC 846B Trouble/week sound?

[bowtie427ss]

Apologies Zilch, the mind fog, dim lighting, and a fleck of debris combined for a genuine "faux pau", they are indeed AS-101, sorry for creating unnecessary confusion.

As a side note i'd mention that when biamping or building new networks, i do not cross below 1200hz for ANYTHING on an 811. Depending on room size and acoustics i'm very happy running the 806/811 with no eq, but then again my ears aren't exactly "youthful" anymore.

Again, i guarantee everyone's mileage will vary at least slightly................

 

[Ocupatto]

Interesting discussion.

I am the culprit who started and owns the 846B's with EV T-35 tweeters. They sound great to me - but when Zilch informs me of another tweeter to use that is better, I will do that. For now, it works just fine.

Thanks.

-Storm.

:thmbsp:

 

[macaltec]

Amen Storm. I've heard alot of people talk down about the EV T35 but no one really offers an alternative. My issue is that the horns should cover the HF without the aid of an "add on" as claimed/advertised/mentioned and so on. Especially for the price they command. I like Altec but it seems they are just one big midrange lacking in both HF and sometimes LF.

 

[Ocupatto]

Mac -

Do you think I should remove the EV's?

Yeah, everyone is down playing them - but you are right, no one is giving a solution or finding a better tweeter.

Thanks.

-Storm

Amen Storm. I've heard alot of people talk down about the EV T35 but no one really offers an alternative. My issue is that the horns should cover the HF without the aid of an "add on" as claimed/advertised/mentioned and so on. Especially for the price they command. I like Altec but it seems they are just one big midrange lacking in both HF and sometimes LF.

 

[bowtie427ss]

I've heard alot of people talk down about the EV T35 but no one really offers an alternative.

The EV T-350 is a vast improvement over the T-35, it can be found in the old style alnico version with a horn flare very similar to the T-35. The newer ones with ferrite motors and cheek type horns are the best IMO, the Peavey HT94 is also a close facsimile.

Personally, i like these for the price of admission, it's a Selenium ST-320, a clone of the JBL 2405 slot tweeter. This is the older all aluminum housing version, still pop up now and then on that auction site, i haven't heard the newer all plastic version.

 

[Zilch]

We measured various tweeters and settled on APT-80. Liked Bob Crites's (BECtoo) CT125, but opted for the smaller footprint of the original Eminence horn.

With any of them mounted outside the horn there's massive combing and time-alignment issues; the tweeter has to be crossed below 6 kHz due to limited bandwidth of 806A drivers we have measured.

Mounted in the horn, there's shadowing and still the time-alignment problem to deal with.

The answer to all of that is a driver that actually plays VHF, and we're moving to comparative listening evaluation of these two approaches, now.

Personally, I think Macaltec's got it right, and am working on Model 19 now. 811 and 511 both support VHF if the driver delivers; thus far, vintage Altecs don't....

 

[Zilch]

The EV T-350 is a vast improvement over the T-35, it can be found in the old style alnico version with a horn flare very similar to the T-35.

T-35's hardly even a tweeter by contemporary standards, and the one report we have of T-350 measurement indicates uneven response and a precipitous drop at 14 kHz.

Someone wants to send me a couple of the radial cheek version, I'd be pleased to measure them. I can't get the sample similar Ramsa horn I have to mount on stock threaded-throat drivers to test, alas. Metric or something, in any case, it don't fit, and it's not mine to bust trying.

Converting a two-way in to a successful three-way is not a mere matter of slapping on a tweeter, unfortunately....

 

[Tom Brennan]

I think the T-350 is being confused here with the ST-350. The T-350 used a huge Alnico magnet on a diffraction horn similar to the horn of the T-35.

The ST-350 used the same ferrite motor as later T-35s but with a constant directivity "buttcheek" horn. The ST-350 should be used with CD horn compensation for extended response.

 

[Zilch]

http://archives.telex.com/archives/EV/Horns/EDS/T35A EDS.pdf

http://archives.telex.com/archives/EV/Horns/EDS/ST350B EDS.pdf

 

[dgwojo]

I have the ST-350A's, they have fairly huge round magnets, they seem to be more efficienct than T35's but less efficient than my T350's, Dave.

 

[Zilch]

I have the ST-350A's, they have fairly huge round magnets, they seem to be more efficienct than T35's but less efficient than my T350's,

Running them with the requisite compensation's gonna give up efficiency. Are you doing that?

CD horn's also "distributing" the energy as opposed to concentrating it. I'm finding it's tough to mate them with high-efficiency woofers unless the driver has really high sensitivity to start with....

 

[Ocupatto]

So, scrap the T-35's and replace them with, what?

Thanks.

-Storm

:scratch2:

 

[Zilch]

So, scrap the T-35's and replace them with, what?

We'll know in another week or so, Storm. A/B listening tests are just about underway.

I THINK we can get you an invitation, maybe, and you can decide for yourself among the several alternatives.... :thmbsp:

 

[dgwojo]

Running them with the requisite compensation's gonna give up efficiency. Are you doing that?

CD horn's also "distributing" the energy as opposed to concentrating it. I'm finding it's tough to mate them with high-efficiency woofers unless the driver has really high sensitivity to start with....

I'm running mine with a 3.3 or 4.7mfd cap in parallel with the horn driver, the Lpad is driving both, the efficiency is almost a perfect match to my ears, I don't have anything to do measurements with so I can't confirm output levels. I'm not into specs, just good sound, Altecs never struck me as a speaker with great specs, afterall, they were meant for large spaces like a theatre and to top it off, they're normally behind the screen. I'd love to tweak my systems with an analyzer some day just to see if there's much difference to my ears, thing is, I'm already happy with their sound. Dave. :yes:

 

[bowtie427ss]

I'm not into specs, just good sound, Altecs never struck me as a speaker with great specs, afterall, they were meant for large spaces like a theatre and to top it off, they're normally behind the screen. I'd love to tweak my systems with an analyzer some day just to see if there's much difference to my ears, thing is, I'm already happy with their sound

Ahhhhhhh the voice of reason is music to my ears.

I think it's important to remember the "human factor" in this, keeping in mind that we all hear differently with the result being: just because a speaker is "analytically perfect", doesn't necessarily mean it's sonically perfect in the ear of every listener.

We all have individual preferences with regard to sound and source.

In my experience i've found the best sound comes from speakers that don't inspire me to add inline eq or other "effects" to color the source signal.

For me, i've come to prefer the sound i get from my '60's technology born, HF subdued, jagged responding Altecs.

Just my totally non-inflammatory .02................ based entirely on opinion and prference.

 

[Richard C.]

Other tweeters tested?

We measured various tweeters and settled on APT-80. Liked Bob Crites's (BECtoo) CT125, but opted for the smaller footprint of the original Eminence horn.

Zilch, I guess I missed it, but when did you test these other tweeters, and what were the results? Was it by ear or tested with response curves? I know the marketing hype for all tweeters is always 20 kHz, but I guess not.

Richard C.

 

[Zilch]

I'd love to tweak my systems with an analyzer some day just to see if there's much difference to my ears, thing is, I'm already happy with their sound.

All the more reason, of course. What's good? What's better? Why? How can you help others get there? The entry fee is $300 or less.... :yes:

For me, i've come to prefer the sound i get from my '60's technology born, HF subdued, jagged responding Altecs.

Well, here's where we part ways, of course.

Kinda looks to me like that Altec guy is actually holding a measurement microphone those many years ago; I ask myself what those four VOTTs were reproducing. :

As Tom points out, if you look at the ST350 data sheet, unless you're using the requisite compensation network, it's a midrange driver peaking at 3 kHz and down 10 dB at 10 kHz, i.e., not even a tweeter.

Properly applied with compensation, it looks to go out to ~14 kHz successfully, plenty good, perhaps, but not up to contemporary fidelity standards.

I don't much trust specs myself, especially old ones like those, compiled when the best available measurement technology wasn't even up to the capabilities of what we can do at home ourselves today. I'd certainly be measuring that driver/horn myself before using it in any system, and trying out the several compensation schemes suggested there for comparison.

Look, this is pretty simple, really: Unless a system is capable of accurately reproducing the full audio spectrum, it is adulterating the program material the pros have provided for all of us to enjoy. That coloration precludes our hearing the music as they intended. We make it worse misapplying speakers in our own spaces.

Is it possible to have a system that plays the full spectrum accurately and still sounds like poop? Sure. I've measured plenty of those, and built quite a few myself, in fact. The challenge is to figure out why, and fix it.

I've apparently got some AKers rethinking the subjectivism vs. objectivism issues, and if this results in more open discussion of them in public forum, that's good, in my view, and if it also results in more audio hobbyists making the effort to figure out what it's all about, so much the better, even.

Personally, I don't give a flying whit what other people listen to. But I DO care that those who might be interested (recognizing also that there are plenty who AREN'T,) have available to them the resources necessary to competently maximize potential enjoyment of their gear and the hobby itself.

If "The care is not there," as someone recently responded to me here, well, that's fine, too. Just put me on "Ignore." I am not offended, and I certainly do not intend that anyone else should be, either.... :thmbsp:

 

[Zilch]

Zilch, I guess I missed it, but when did you test these other tweeters, and what were the results? Was it by ear or tested with response curves? I know the marketing hype for all tweeters is always 20 kHz, but I guess not.

T-35 GETS to 20 kHz, but down ~24 dB, is all.

We did the JBL ring radiator comparisons nearly two years ago, and some dome tweeters at the same time, as I recall:

http://audioheritage.org/vbulletin/showthread.php?t=6368

I did preliminary measurements on EV, Crites, and Eminence last month. "Preliminary" was enough to kick out the T-35, as is obvious from the curves I've posted above. No surprise, really, they seem to populate "junk tweeter" boxes most everywhere; I just needed to verify.

I still have some piezos, planars, and others to do yet. For my own part, it's clear that adding a tweeter to an 811-based system is not a simple task, and perhaps not the optimum approach, either, now knowing that the horn itself will support VHF without beaming excessively.

Have I done polar response studies on 811 and 511 to verify that? Nope. That's an expert "Tilt the horn and watch the RTA" finding....

 

[bowtie427ss]

Zilch, i absolutely applaud what you're doing, and follow with great interest, please don't take offense at my comments or opinions.

My point in brief since i don't want to derail a great thread is simply that even tho the classic Altecs may fall well short of ruler flat response and high frequency extension, many of us are unlikely to modify or change them.......... much.

However, thanks in very large part to the information you've provided, many of us will be able to avoid "cloning" the negative attributes of those classic designs.

I'm also a DIYer to an extent, and i respect/admire/envy what you're doing, and will most assuredly use your findings and recommendations in future projects.

 

[Zilch]

My point in brief since i don't want to derail a great thread is simply that even tho the classic Altecs may fall well short of ruler flat response and high frequency extension, many of us are unlikely to modify or change them.......... much.

Well, for ~$250 the pair, you can be the first AKer to try this in their existing sytem, and then tell the forum at large whether the Zilchster's got his head up his ass or not.... :thmbsp:

[I don't sell none of this stuff, folks.... ]