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In Reply to: RE: Fostex alnico tweeters posted by Jim D. on December 10, 2016 at 05:34:49
I read that a lot of you fellows are using a 0,67 uF cap in series with your 8 Ohms tweeters.
That will give you an Xover point of 30 000 Hz, which is way above human hearing and also most playback sources.
I use a 1,5uF cap giving my Fostex T90a a 13 000 Hz Xover, which I feel would be better match to my Radian 750/200hz tractrix horns.
Follow Ups:
Still passing audible freq's...7.5 Khz @ 12db down, 15K @ 6db down
using your 30K x-over point. Still useful as a supplemental
super tweeter.
Small correction, but your point still stands.
The 30k crossover point is the -3db point so 15k would be at -9db and 7.5k would be at -15db
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
No, the turnover is still in transition at the -3db (cutoff) point. It will be -6.02db at 7.5k.
The example was a .67uf cap in series with a 8 ohm tweeter. A first order filter.The crossover point for a BW filter is the -3dB point and for a LR it is the -6dB point.
All first order filters are BW filters.
A .67uf cap in series with a 8 ohm tweeter will cause the -3db point to be 29,693 Hz.
From that -3db point on, the signal will fall an additional 6db per octave.
One octave below the crossover point will be at -9db
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 12/15/16
No, it isnt. At the 3db point, the slope is still transitioning. its still on the knee of the curve.
"At the 3db point, the slope is still transitioning. its still on the knee of the curve. "OK, did I say it wasn't?
My point is that the stated crossover frequency is the 3db down point when using a 1st order filter.
Do you dispute that?
"No, the turnover is still in transition at the -3db (cutoff) point. It will be -6.02db at 7.5k."
How do you figure that?
The 3db down point of his filter is at 30kHz. At 15kHz if will be nearly 6db further down and at 7.5kHz another 6db below that.
I feel like we are having some trouble communicating with each other.
Maybe it's me, maybe it's you. :-)
Sorry, I know we were talking about a high pass filter and this chart is of a low pass filter but it's the first one I found. It still show what needs to be seen.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 12/17/16
7.5k was in error. it would be -6db at one octave below the cutoff. It seems that you are saying it would be -9db at one octave below cutoff, but it is -6.
Yes, you are right.
I see that now.
My apologies.
The filter is still on the knee, as you said, for the first octave after the 3db down point. The filter only reaches the 6db per octave rate of fall after that. Actually the filter takes a little longer than that to reach the 6db per octave fall rate.
I guess that means my tweeters are playing harder at the lower frequencies than I thought.
Thanks for the correction.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
No need for apologies. Learning is what this is all about. Sharing knowledge which would be much harder before the internet. I have learned some things from you over the years.
And yet in experiments with super tweeters with a claimed low end of 15K, I seem to be able to tell when they are in the system and when not,
Blinded, of course, which is a pretty easy test for me as while my hearing is good for an old guy, my eyes are pretty bad.
I feel there are resultants on high, that come down the scale into the midrange. As we age, we hear those resultants, and judge easily what sounds real or canned.
I recall Bob Fulton, in about 1983 give or take, tell me about an 80+ year old woman on his Listening Panel, who couldn't hear a watch tick, and had 'nada above 5K. One day, Bob removed the fuse from is tweeter section's highest-playing driver, maybe, lets say, 32 K on up to 100K, and the Old Woman blurted out to Bob " What Happened To The Highs ".
Jeff Medwin
I thought humans "hear" the real high stuff through the bones in our head.
I don't know, I read that somewhere.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Boyk's work found here .
Perhaps the question is not what we *hear* as much as what we perceive .
.
Have Fun and Enjoy the Music
"Still Working the Problem"
Hi Estat!
That's an excellent point you made about it not being what we *hear* as much as what we perceive. That's why I said in my first post in this thread; --- adding super-tweeters must create some psycho-acoustic effects that the brain perceives on a subconscious level.
I'm listening to: Shine On Brightly by Procol Harum
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
Gets played here often.
Those first four are ageless records.
Music and lyrics that grab your interest even after hundreds of listenings.
Glad to hear SOMEONE else appreciates them!
Hi Rick I grew up listening to Procol Harum. A Salty Dog and Shine On Brightly are my two favorite recordings by them! But of course their first Procol Harum was also an amazing piece of work. I also really like Procol Harum Live: In Concert with the Edmonton Symphony Orchestra very much too. IMHO these recordings from the late 60's to early 70's are still very fresh.
I'm listening to: Across The Rubicon by Silhouette
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
When most of us can't hear above 10k it doesn't mean we can't hear above 10k. It simply means we can't hear 10k at the db level of the 2k-5k frequencies. This is shown in the Fletcher-Munson curves are is exaggerated as we age. If we boost the level at 10k we can hear it. So even though the super tweeter might be -7.5db down or more within the hearing range and rising to 0 or plus db at our crossover frequency which might be out of our hearing range, we are still adding (tweeter plus super tweeter) to the db level within the upper limits of the hearing range (rising from 5k to 15k) while not adding to the 2k-5k range. In other words by adding a super tweeter, aren't we providing a hf boost within our range of hearing and flattening the hf curve? Even if we have not truly flattened the frequency curve we have added to it which is something we will hear and the extent of what we hear will depend on not only the crossover frequency providing the additive curve, but our own hearing range.
These guys are using 1st order crossovers, in some cases without padding down. I reckon the tweet would be (easily) heard when used like this.
Cheers,
91.
"Confusion of goals and perfection of means seems to characterise our age." Albert Einstein
I do not use the tweeters in a conventional tweeter duty. In this arrangement, many call it " super tweeter". Yes, it is about 30kHz, I also try 25kHz (about 0.8uF). Try it, it adds "ambience" to the listening room and virtually increases the size of stage when done right. At 1800 Hz XO to my Altec 614's, 1800 Hz up to 22kHz is taken care of by the HF driver(Altec 802) and not the tweeter we are discussing. Cheers!
Edits: 12/12/16
That added ambience is probably noise. Have you listened to the super tweeter by itself? There is no musical material there that you can hear.
Alan
As I wrote, I own a pair of Fostex T90a and I am rather ambivalent on what to think.
Sure when The X-over is at 15k (1st order) they will sound way below that. But when you guys X-over at 30k, one must wonder how much is music, and how much is noise within the human heariing range (maximum 17khz when you are around middleaged).
Beond that, the CD-medium cuts of really hard everything above 22khz, so what kind of signal reaches the tweeters at those freqencies?
with no L-pad, and your horn tweeter in question is 6dB more sensitive that the rest of your speaker, then you are right in line at 15K and only 6dB below the rest of the speaker at 7.5K.
,
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 12/19/16
Hi ahendler.
You were 100% when you said, a super-tweeter adds no musical material to the music info ---that you can hear! This is something most audiophiles attempt to prove to themselves by listening to the super-tweeter itself. However doing this isn't sufficient enough to come to the conclusion that " the added ambience that's heard when using a super-tweeter is probably noise." I know what I'm talking about because I previously added a pair of Fostex T900a to act as " super-tweeters to my Dayton PS220-8 single, full-range drivers.
The T900a super-tweeters were crossed in using a 6dB crossover @ 10 kHz and covered the frequencies of 10 kHz to 38 kHz. I believe that despite the fact that I don't hear above 15 kHz, adding super-tweeters must create some psycho-acoustic effects that the brain perceives on a subconscious level. I say this because I heard the same sonic improvements to my system that you can read about super-tweeters from most anyone else who's super-tweeters.
Almost all audiophiles who've used them will say something basically like what John Potis said in his MuRata super-tweeter (TG1954: the MuRatas are true super-tweeters covering from 15kHz to 100kHz) review for 6moons: ---there's an increase in vibrancy and detail that they bring to the treble as you would expect. But that's only the beginning of their story. Cleaner, more sharply defined and more articulate bass is what will amaze you and an easily perceived bump in midrange articulation may just astound you. And add to that greatly improved transient snap, microdynamics and drive.
So no, my friend it's not just noise that added by super-tweeters. They definitely add to the enjoyment of listening to your music and in a very noticeable way...
I'm listening to: Use Me by Vanessa Fernandez
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
"The T900a super-tweeters were crossed in using a 6dB crossover @ 10 kHz and covered the frequencies of 10 kHz to 38 kHz. I believe that despite the fact that I don't hear above 15 kHz, adding super-tweeters must create some psycho-acoustic effects that the brain perceives on a subconscious level."Actually, in your implementation, they usefully covered the frequency range of about 5kHz and upward, given your 10kHz at 6 dB x-over. Further, since an 8 inch driver will severely beam at upper frequencies (as well as have decreasing output even on-axis), another part of the improvement can be attributed to a better ambient sound field. This is not subconcious, it's readily and audibly apparent.
Edits: 12/14/16 12/14/16
Never said you are not hearing an improvement in sound when using a super tweeter. In the 60's when we first brought in the Dolby-A noise reduction system to our studio everybody though high frequencies were being rolled off. But when we took measurements Frequency responce was the same with or without Dolby. We spent a lot of time trying to figure out what was going on. We discovered that if you took a recording and added random noise from 12khz to 20khz there was a definet increase in frequency extension along with increased resolution in detail. So you guys are correct in what you are hearing, you just have the mechanism wrong. Interesting passive aggresive use of the phrase "my friend" or is it sarcasm?
Alan
Alan when I say " my friend " there's nothing passive aggressive or sarcastic meant on my part. To me you're one of my online audio " friends. " Now while I suppose audio acquaintance would be a closer rendition of what we actually are. I feel using the term " my acquaintance " would come off more like what your suggesting I meant! Trust me, I'm not a subtle type of person. When I'm being sarcastic or aggressive ---{ I'm never passive in my aggressiveness }--- you'll definitely know what I'm being. In the meantime I suppose this will be one of those topics where we'll just have to agree to disagree until someone does a test comparing the same exact song, in the same room, on the same audio system, at the exact same volume. And then adding both random noise from 12 kHz to 20 kHz and a super-tweeter and have people listen for whether or not there are audible differences between those two, or not. I believe it would be a waste of time for us to discuss this any further as you won't be able to convince me I'm wrong in my beliefs and I'm quite sure I won't be able to convince you you're wrong in your beliefs either. So until those tests are run, neither of us will know who's opinion is correct...
I'm listening to: Feel The Rhythm by Daria
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
This is one of the ongoing problems in audiophileland. Armchair "audio experts" develop "beliefs" which, only when reality smacks them on the head will they change, if then. This is despite that their beliefs are often unfounded, unproven, incorrect, or based on what they read in some audio magazine or from other audiophiles.
Hi Inmate!
I can definitely see some truth in what you said. But unless extensive tests are done, we'll never know who's right or wrong will we? It's quite possible one of those armchair "audio experts" you spoke of, might have actually developed a "belief" that's correct!
I recently had an a new audio friend that I met at one of our local Audio Society meeting over to listen to my audio system, a Mastersound Reference 845, Integrated amp, YBA Genesis CD4 CDP and Beauhorn Virtuoso speakers. As we spoke between recordings he asked why I had 3 different pairs of ICs, 4 different pairs of speaker-wires and 3 different digital wires. I replied that whenever I make a change in my system by replacing say one CDP with a different CDP or if add a new audio component, like the Musical Paradise MP-D2 DAC I'm looking at, then I try all these wires over again. So that I can see which one sounds best with the new system configuration!
He laughed a little and said to me " You really believe those different ICs, speaker-wires or digital wires sound noticeably different? I told him I know they sound different and I'll show you they do. After replacing the ICs we were using with a different pair, I noticed a look on his face that revealed to me he heard, not just a difference, but a very noticeable difference in their sonics! Which is exactly what he said as soon as the song stopped. His problem was created before coming to my home. He had tried different ICs on his system, but, didn't hear a significant difference and came to the immediate conclusion that 1) wires all sound the same and 2) those who say differently are just fooling themselves. That's NOT what he believes today.
Inmate, my friend, if there's any "problem" with audiophiles/music lovers, it's that they often form staunch opinions based on too little knowledge, experience, or trials. We all only know what we know about audio based from what we've heard. Then we form opinions based on the knowledge we have or we create a post on some audio forum based from that same audio knowledge. While the reality is that those opinions we've formed could actually change based on the very next audio system we listen to...
I'm listening to: Across The Rubicon by Silhouette
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
"unless extensive tests are done, we'll never know who's right or wrong will we? "
If you'd read your AES and ASA journals, you'd know that a plethora of tests, experiments, studies and research have been done for at least 70 years!
Ya gotta get your head out of the audiophile mags and read some real science. Start here: "Why You Hear What You Hear" by Dr. Eric Heller. Go from there.
:)
I am not an Armchair audio expert. I am a degreed electrical engineer, a longtime recording engineer at the largest recording studio in Chicago and technical adviser to two brick and mortar high end audio stores in Chicago. I am the engineer on Buddy Miles Them Changes album, have recorded the Chicago symphony, over 2000 TV and radio commercials and many location recordings. If I am not qualified to comment about this hobby then I am not too sure that you are qualified either. Next time try to get your facts straight before commenting.
Alan
My post was directed at tubeguy1954. Did I put it in the wrong place?
:)
Sorry if I misunderstood. When there are a lot of posts it is sometimes hard to determine who is being referenced. Well at least I got my credentials out there again. I do want to say that this is a free and open forum. Not really a professional forum even though there are pros here. I do not want to turn off anybody from posting here no matter what there background is. Anything that spurs conversation is good although I wish we, including me, would keep personal attacks out of our discussions
Alan
Hi ahendler,
I hope you're not suggesting that I personally attacked you? If you feel I did please include a link to the post where I did so ok? I'd like to reread that post. Perhaps you saw something that wasn't there like when you said I was either being passive-aggressive or sarcastic, when I wasn't being either to you?
I'm listening to: Across The Rubicon by Silhouette
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
No, no, I did and do not feel attacked by you at all. As I said just felt the phrase "my friend" was a little strange. No problem, I always enjoy your posts
Alan
Alan I just read your other post and I can tell from your response your a person of integrity. If you read my other response it will explain more that I don't wish to repeat here! In all sincerity I wish the best "my friend!"
I'm listening to: Across The Rubicon by Silhouette
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
"then I am not too sure that you are qualified either. Next time try to get your facts straight before commenting.""I wish we, including me, would keep personal attacks out of our discussions"
Okee doekee. ;)
:)
Edits: 12/14/16 12/14/16
I agree with everything you just said. I also apologies for my comment on My Friend. I have experienced a lot of rude behavior on this site and I guess I just have come to expect that. Happy holidays
Alan
Alan,
That's quite alright! I, too, have experienced a lot of personal attacks because of some opinions I have. IMHO there are some audio arguments that will ever be won. One of those is: Do wires have a unique sound of their own? I believe if you see two people discussing the POV that is the opposite of what you ---{ and by you, I mean anyone who has the opposite POV than the one being discussed }--- believe on this issue. It's almost always best to stay out of their discussion!
Why do I believe this? Because I've yet see anyone from one side of this argument win a convert to the opposite side of this argument. Usually a person from the opposite POV will join their discussion and usually the conversation stays civil initially. But as more people join in on both sides of this argument/discussion/debate, some will start to make mean comments about one of those from the opposite POV and this inevitably leads to name-calling, disparaging comments about each other and always near the end, before a moderator intervenes, just one side attacking the other!
I never understood why people let this happen over & over again. But, in any event it was nice talking with you again. I can tell that although we might have different beliefs about audio, your a gentleman and I respect that aspect of your personality --a lot.
I'm listening to: Across The Rubicon by Silhouette
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
Perhaps I am just too slow to pick up on aggressions and insults , but in my opinion High Efficiency Asylum is a quite civilized website compared to many others I regularly visit. That is one of many things I like about our
forum.
Hi Don,
I'd have to agree with you.
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
Well past the sensitivity of your Dayton full range drivers (95.6dB)
Even I could hear them at that level. ;-)
Ivan,
You weren't the first person to bring that issue up. Almost all my local audio friends did as well. But remember I cannot hear above 15 kHz so the T900a being a good 5dB more sensitive shouldn't matter much. Granted I didn't have an L-pad, but a friend threw a resistor in the XO somewhere to make them almost even volume wise. My point is if I cannot hear above 15 kHz how did I hear what I'd call more extended highs, with more "air" around instruments & singers? If I had an equalizer and boosted the frequency at 5 kHz that wouldn't be the effect I'd expect to hear! The weirdest part is the bass seemed more taunt and deeper as well. Go figure...
I'm listening to: Feel The Rhythm by Daria
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
If you just use a cap for 10K, it'll pass plenty of highs below
that point. Only 6db down at 5K. So it's covering well more than
the "10K-38K" you stated.
Hello Alan! I remember you from my Magnepan days!
Anyway, no but I tried. The Fostex is no match to an 802 doing HF duty in my config. As for the freq range that it cover as a super tweeter using 0.68 uF, try it, but you have to implement an LPad to attenuate the amplitude so as to blend in with the HF driver. It is not "just" noise as you call it. Difficult to explain really until you try it. I was a non believer too but I heard it from a system and added it to my set up.
See my above post showing how adding noise at high frequencies causes the effect you are hearing. I tried a super tweeter with a pair of Lowthers and they had no effect at all
Alan
... what can I say? There's sonething there and I am telling you from what I am experiencing.
Your 3.6R is what, 40kHz I believe. Connect a low pass filter at say 20kHz cut off to the ribbon and you will hear the effect of losing the "subtle" sound (or harmonics maybe?)coming from the tweeters upper range.
Happy holidays!
Hi amandarae!
You're 100% correct all one has to do is disconnect their tweeter and listen to how much the midrange and bass changes without a tweeter to understand how a super-tweeter can also greatly influence the sound of the music as well...
I'm listening to: Feel The Rhythm by Daria
Thetubeguy1954 (Tom Scata)
Central Florida Audio Society -- SETriodes Group -- Space Coast Audio Society
Full-range/Wide-range Drivers --- Front & Back-Loaded Horns --- High Sensitivity Speakers
No. My Radian 750 with alu membrans dropp of by 15 kHz and My thought was to extend that up to 20 000 Hz.
Perhaps with My lowish roll off, a 30k Hz would be strange with a gap i the frequency range?
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