Altec and open baffle

Altec Open Baffles, etc.

Postby s2kov » Wed Sep 15, 2004 4:16 pm

thanks, kya lng nung una parang nalalakihan ako when he offered me this. anyway, we already had an agreement.


arnoldc wrote:s2kov, if i were you, i'll get it. it's a 15 incher with 113dB sensitivity with 35watts input form 500Hz to 1kHz. its frequency range is from 20Hz to 2kHz and you will need a horn tweeter from 1.5kHz up. best to use a mid range and a super tweeter.
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Postby BonD » Wed Sep 15, 2004 4:44 pm

Pareng Andoy,

Wag mo nang pakawalan yan...kunin mo na.. :evil: :D
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Postby mozilla » Wed Sep 15, 2004 7:38 pm

Galing arnold! Wow kailan kaya ako makadaan dyan?
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Postby troporobo » Thu Sep 16, 2004 8:32 am

Arnold - I noticed that someone on AA recommended the Fostex FT66 for your OBs. I have a pair of these that I bought for a project that I haven't started yet. If you're interested you're welcome to borrow them for an experiment. It would only be fair, since I "borrowed" your idea for an acrylic flexy! Let me know if you want to give them a try, Robert
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Postby arnoldc » Thu Sep 16, 2004 8:44 am

troporobo, thanks sir. :)
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Postby Killer Mike » Thu Sep 16, 2004 10:43 am

Arnold, i'm still familiar with the sound of those huge speakers although mine is a 12" sansui. Iba tumirada ng tunog :) nakakalungkot lang dahil nasunog ito 2 years ago :( Those Altec speakers are for keeps :D
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Postby arnoldc » Thu Sep 16, 2004 12:14 pm

mike, to these ears, they do not sound like the commercial speakers i've tried (i understand they were commercial before, but that's another story) pati ticks and pops ngayon mataba at malaki ang tunog :D

teka mas malaki yung iyo, 12" akin 10" lang...
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Postby arnoldc » Thu Sep 16, 2004 4:53 pm

hi joseph, i found out that the ElectroVoice T35 rolls off early (-4dB at 15kHz) and has low power handling capability (5-7W RMS) which could be a concern for me since i have a 10 watter pentode.

right now i can hear the "hole" in the FR and thought that the Infinity is not really picking up at 3kHz as i originally suspected.
Last edited by arnoldc on Thu Sep 16, 2004 5:34 pm, edited 1 time in total.
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Postby red76 » Thu Sep 16, 2004 5:15 pm

arnold
already tried REM's Beds Are Burning and i'm pleased


Midnight Oil ata yun... :D


troporobo
Arnold - I noticed that someone on AA recommended the Fostex FT66 for your OBs. I have a pair of these that I bought for a project that I haven't started yet. If you're interested you're welcome to borrow them for an experiment. It would only be fair, since I "borrowed" your idea for an acrylic flexy! Let me know if you want to give them a try, Robert


I think that was me... O yan Arnie, mukhang ma try mo muna without the risk of ordering without audition (order from Mickey? :) ). BTW, kung mahiram mo man, try mo gamitin ang xover calcualtor: http://lalena.com/audio/calculator/xover/. If the 406 is relatively linear from the midband upwards 4kHz w/out losing efficiency, pwede 5uF cap in series with 0.33mH wirewound air core inductor for the tweeter. Pag nakuha mo na yung "right" values using cheap caps and coils through trial and error, you could try Fostex copper/tin foil caps and Jantzen 20awg air core coils.

Kung eBay hunt ka, try the EV-T350 (21kHz - pang ride and crash cymbals!).. Yung T35 mas early ang rolloff and slightly less efficient.
http://www.geocities.com/michael_gesual ... 5B_350.jpg
http://www.geocities.com/michael_gesual ... _350_2.jpg
You can try a 2.2uF cap in series with a .33mH coil for these.


s2kov,

The 515 will work well with bass reflex or hornloaded encolosures (front and/or back), but is not really ideal for OB. I think pwede sya sa OB with a correction circuit, but there will be some compromise in efficiency.

P.S.

Altec Bicones are good for OB, plus it's a linear widerange (circa 13kHz rolloff).
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Postby arnoldc » Thu Sep 16, 2004 5:30 pm

fred, grabe. kailan pa kinanta ng REM yun? ha ha ha :D

i will be crossing over at 3kHz and will need around 6.6uF if i will use the Fostex FT66.

yang ElectroVoice di ba nagkalat sa Raon dati?
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Postby Tony M » Thu Sep 16, 2004 6:11 pm

Hi Arnold,

I am glad that the speakers are in good hands and sounding nice. That was my previous speakers that I bought from ebay two years ago together with another altec 601c that i am now using. I was not able to use and hear them before patispetrus bought them. My idea was to paired this with vintage alnico tweeters which patispetrus also bought a pair from me. This are telefunken dome tweeters. Try borrowing these tweeters from him.

Hope this will complement your 406y.

Enjoy :lol:

tony m
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Postby red76 » Thu Sep 16, 2004 6:25 pm

It would be pushing it a bit kung 3kHz sa FT66 (recommended xover freq: >3.5kHz), pero kelangan mo nga malamang kasi may dip sa mid. The only way to find out is to try.... Anyways, yung cutoff freq naman ng FT66 is 2.5kHz...
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Postby setup1 » Thu Sep 16, 2004 10:07 pm

arnoldc wrote:hi joseph, i found out that the ElectroVoice T35 rolls off early (-4dB at 15kHz) and has low power handling capability (5-7W RMS) which could be a concern for me since i have a 10 watter pentode.
right now i can hear the "hole" in the FR and thought that the Infinity is not really picking up at 3kHz as i originally suspected.


I use specs only as a guide especially when dealing with vintage units. According to my '59 Lafayette catalog, the EVT35 is good up to 18khz, perhaps your information is based on contemporary standards wherein the measurement procedure is more appropriate to a dome tweeter and does not take into account the nature of dispersion of a horn tweeter.

When I started venturing into vintage hi-fi I did a lot of research and asked opinions from more experienced ears I trust. Later on I learned to rely on my ears and intuition. Back in the 50s when a lot of these items were designed, there was really no measurement standard only manufacturers standards, which in some cases were more valid in the real world but not suitable for marketing hype. Chances are "old" specs were more modest than later in the '60s when specs were standardized.

For ex: the Altec 755A is only rated 70-13khz while the later 755C is 40-15khz. However it's a universally known fact that the 755A has much greater top end extension. Edgar Vilchur even used it as the midrange tweeter in the AR1, which was discontinued when the 755A was replaced by the 755C. Likewise, the Altec 3000 tweeter is rated only up to 20khz, but to my ears it has more top end extension than a Fostex FT17H.

With regards to power handling, as long as you place a proper value cap in series a 10W amp will not fry the tweeter since the cap limits the amount of energy/power going to the tweeter. BTW, the 755A used as fullrange is only rated 8W max and I use them judiciously with an 8W SE300B amp to play Mahler with no problems.

If you're really hearing too much of a "hole in the middle", this is probably caused by a mismatch in efficiency and/or maybe your x'over point is too high. If the Infinity tweets can handle it, I'll try to x'over around 2khz. The Fostex FT66 recommended by red76 might work but it may still be pushing it. The problem with small horn tweeters like the Fostex FT66/FT17H, T35, Altec 3000 and etc. crossed above 2.5khz is that, they have to be mounted in co-axial configuration to properly function like an Altec 601, EV TR12rx or LT12. Actually Altec used the 802/515 driver combination in the 604 series which crossed at around 1.5khz to 2Khz depending on vintage.

If you want to solve the problem cheaply, use a 3.5" cone tweeter like a Jensen P35VAH or equivalent, add the FT-17H to fill in the extreme top. But the best way to tackle the "hole in the middle" problem with the 406 is a compression driver/horn lens combo that go below 1khz. This will give you the flexibility of hinging at a lower crossover frequency. Think along the lines of an Altec 802/804/811 horn. The later ceramic 902 with aluminum diaphragm is also a very fine compression driver which you heard at Joel's [setup2]. If you want something modern and affordable, check out Parts Express for horn/driver combos from Selenium, B&C and etc. however I cannot vouch for their sonic quality since I have no experience with any of them.

It's unfortunate no one can provide information on the tweeter unit used in the Altec Bolero. If this is unlocked, it would be much easier to find the true nature of the 406 and your problem is easier solved.

Good luck!


JE
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Postby red76 » Fri Sep 17, 2004 12:53 am

setup1
But the best way to tackle the "hole in the middle" problem with the 406 is a compression driver/horn lens combo that go below 1khz. This will give you the flexibility of hinging at a lower crossover frequency. Think along the lines of an Altec 802/804/811 horn.


My thoughts exactly. Get a very good mid-high compression driver and cross it much lower than 3k. This will be more expensive compared to a small horn tweeter but the sonic results will compensate for that espeically if you get a very good horn for it Tractrix (le'c'leach flare), Conical , Sectoral etc.

Kinda reminds me of hybrid Open Baffle Horn speakers made by Klangfilm (Germany).. Like the Bionor and Eurodyn series etc.

Check this out (Altec 808-8B):

http://www.hifido.co.jp/cgi-bin/newhifi ... text_mode=
http://www.lansingheritage.org/html/alt ... s/808b.htm

stereo lab tractrix 1000Hz horns for Altec
http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... 3840269636

Image
Of course you could still xover >1000Hz with these if you wish....
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Postby setup1 » Fri Sep 17, 2004 5:30 am

[quote="red76
Check this out (Altec 808-8B):
http://www.hifido.co.jp/cgi-bin/newhifi ... text_mode=
http://www.lansingheritage.org/html/alt ... s/808b.htm
stereo lab tractrix 1000Hz horns for Altec
http://cgi.ebay.de/ws/eBayISAPI.dll?Vie ... 3840269636

Image
Of course you could still xover >1000Hz with these if you wish....[/quote]

Hi Arnold and Frederick,

Altec compression driver tips:

Whatever 802 or 806 model you choose make sure the compression driver has the original aluminum diaphragm. Much of the bad rep Altec horns got is due to replacement diaphragms like Pascalite. The only advantage of this type of diaphragm is higher power handling at the expense of slow transients and limited HF extension. Pascalite probably works well in PA applications but not Hi-Fi. Some people also prefer the "technically superior" Tangerine phase plug but my ears tell me the original phase plug found in earlier 802s , 804/806s are better sounding. This phase plug design traces its roots in WE compression drivers [WE555 and 713 series].

JE
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Postby ichabod » Fri Sep 17, 2004 7:14 am

Joseph, on another vein but Altec still, model the 403 (full rangers), you think I can use the same close box enclosure you mentioned in your website? I remember reading that close box Chong Ong gave you. I wonder if he's the same guy I bought some of my amps from ebay. I'd like to try if I can get a decent sound from these drivers with a Calrad set using 6BM8s. Would appreciate your thoughts on this, and thanks for the invitation to watch you and Albert Tiu in a live "natural audio" I hope concert here in Cebu. If microphones and screechy speakers can be avoided so much the better I suppose?

Just 2 weeks ago, the Chicago Jazz Quartet gave a rousing performance here. Funny thing though, all the sound came from the speakers that were perched way too much on the sides, and I would have been more "forgiving" to the sound tech crew (local) if they were Altecs :-)
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Postby setup6 » Fri Sep 17, 2004 7:28 am

Tony M wrote:Hi Arnold,

I was not able to use and hear them before patispetrus bought them. My idea was to paired this with vintage alnico tweeters which patispetrus also bought a pair from me. This are telefunken dome tweeters. Try borrowing these tweeters from him.



Unfortunately the TFs could not go down to 1.5khz- which I thought was a the frequency that the 406 started to roll-off.

Like what the others have said, I think a mid-horn would be best. Another experiment is to use a fostex 4 incher like the fe103.
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Postby arnoldc » Fri Sep 17, 2004 7:54 am

tony, thank you for getting it here in the philippines :)

tony, joseph, red, nilo,

i'm not sure if it's really a "hole in the middle" that i seem to miss, i'll try to describe and maybe you can further your advise.

if i play Charlene's "I've Never Been To Me", Maureen McGovern's "The Morning After", Sergio Mendez and Brasil 66, the Fool on the Hill Album, any Nancy Wilson, Pat Coil, William Ackerman, Laurindo Almeida - i am in heaven. they sound really great, big, warm, lush, emotional.

but if i play the Eagle's Hotel California album for example, there is definitely something missing above the mids. Neil Young's Decade album can get by on the acoustics, but on the electric tracks, the "grunt" of the guitars are not there.

any thoughts?

joseph, i do not know the efficiency of the 406-8Y... 99dB perhaps? and the Infinity tweets are 89dB probably lower, so there you go, sensitivity mismatch.

joseph, i trust your ears and experience on your recommendations. you have perfectly given me the assurance on the EV T-35, besides they look really nice.

someone in AA called the Altec Bolero tweeters the "mystery tweeter," it seems obvious to me now why.

red, a mid horn is something that is last on my priority, although somebody in HiEff asylum already told me about that as his gut feel tells him so.

nilo, that is definitely a more viable option. another is john poscablo might have something that can pickup from 1kHz up which is also an Altec driver, it just slipped my mind at the moment.

thanks for the assistance and support.
Last edited by arnoldc on Fri Sep 17, 2004 8:44 am, edited 2 times in total.
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Postby arnoldc » Fri Sep 17, 2004 8:15 am

by the way, the guy (Tom Brennan in AA) who has the Altec Bolero tried to describe it. he said -

"The horn and throat do not appear Hepnerish; the first thought that came to mind was that Altec was using Hepner but it appears not. The driver part has a "deep throat" like normal Altec 1" driver of the time, then the horn comes into play, there's a seam where they join. "
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Postby setup1 » Fri Sep 17, 2004 9:25 am

ichabod wrote:Joseph, on another vein but Altec still, model the 403 (full rangers), you think I can use the same close box enclosure you mentioned in your website? I remember reading that close box Chong Ong gave you. I wonder if he's the same guy I bought some of my amps from ebay. I'd like to try if I can get a decent sound from these drivers with a Calrad set using 6BM8s.


I had a single 403A [alnico version] and it was included in the mini review of 8" drivers in the Sound Practices Homebrewer article. In case you haven't read it here's the link:
http://members.myactv.net/~je245/homebrewer.pdf
I could not find a match and during one of those Audiomart swapmeets, I traded it with a Japanese guy for some Stereo Sound "tube kingdom" issues. It's not in the same league as the 755C or 408A but is still a musical speaker on OBs. At that time I didn't have a proper 2 cf cabinet so I wasn't able to try them which unfortunately, is the only way to find out.

There's only one Chong Ong in eBay that I know who trades in audio and I'm pretty sure your Calrads were from him.

I don't know the venue for the concert in Cebu but please say hello after the concert so that we can chat.

Regards,

JE
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