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Hey!
Here's a topic you don't see discussed much here or on any other audio board.
Like many folks on the far side of 50, for a variety of reasons, not the least of which was standing too close to the A7's while performing or attending rock events, I have more or less severe hearing loss above 3K. In my youth I might have told someone like me tough luck buddy, you've lived too long anyway.....But, my plan here is to enjoy what hearing is left.
You'ld be suprised how well hearing aids do to restore some of that but they compress any real dynamics and I want to see what can be done with 12db (probably not enough unfortunately) set according to my audiologist's report.
Now, I've used equalizers from ART and Pioneer (junk). Do any of the professionals or others on board here have any experience with the Altec equalizers? Any favorites? Orban? Urei? Others?? What's a parametric eq?
Whatever I use will need to be bypassable so as not to torture other folks when listening together.
Thanks
Dan Hall
Fairbanks http://www.hostboard.com/forums/ http://www.hostboard.com/forums/
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Dan,
It is a good idea to tailor a system for the hearing impaired.
Some problems:
Noise and age induced hearing loss affects the threshold of hearing at mid and high frequencies, but not the response at high levels so much.
An equaliser will increase the low level mid-high response as well as the high level mid-high response. This will not sound correct either.
Also the speaker system will be asked to produce much higher output at the mid-high range. It may distort, and even be damaged. It may also further damage the hearing.
What is needed is a dynamic equaliser which increases the mid-high range at low levels but progressively lessens that increase at high levels.
Some of the digital eqs will do this (Weiss) and also the BSS (Brooke Sirens) dynamic equaliser (can't remember model No.).
Some of the new DSP based units will do it also.
You may be able to get the required response curves from your hearing specialist and get an engineer to program a suitable unit.
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Wow, I didn't know most of that:
But it all makes sense. No wonder music sounds so much better when played loud.
I don't know for sure but I imagine that what were talking about here is the kind of thing that a sound card does laying down. I checked the Weiss and BSS websites; hehehehehehehehehehehehehe.... I won't be going there until that stuff shows up on the no reserve list on E-bay. Anyway, I've heard somewhere that Soundblaster or somebody even has a card with a tube on it! Hmmmm. I don't begin to know how to do a search for the suitable software, but I think I know a guy who does.
Hey Todd.....do these non altec discussions need to go elsewhere?
Dan
Fairbanks
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A cheaper solution:
Feed the output of your preamp into an equaliser, connect that to a compressor, connect the output of that to one input of a mixer.
Also, connect the output of the preamp to another channel of the mixer.
Adjust the compressor so that it starts compressing at 85 dB SPL from the speakers on a ratio of 2:1, attack fast, release slow.
At a low level from the speakers, say 80dB SPL,(no compression active)adjust the equaliser for a good sound.
Set the mixer so that the compressor/eq chain has about 6 dB more gain than the direct chain.
In operation at low levels tha eq sound will dominate, as the level increases the compressor comes in reducing the gain of the eq chain. At about 91 dB SPL both chains will be equal level so the amount of eq boost will be effectively halved. At about 100dB SPL the eq chain will be basically ineffective so you will have a flat response from the preamp.
Adjust the relative levels to get the sort of response that sounds good to you.
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Tough luck buddy, you lived too long anyway!!
Just kidding Dan.
I basically agree with Marcus. The best bet is to get custom adjusted DSP based correction based on your specific hearing deficit. These will give you the most precise correction and may be variably adjustable at lower and higher levels as required. Get your Audiologist to run narrow bands at lower and higher levels and then plug in the deficits at that freq to the DSP. Remember that the hearing is not flat across the audio range instead it is most sensitive in the midrange freqs and drops at freq extremes. This is also variable depending on the actual SPL. In other words at low volume you perceive less bass at higher volumes more. The Fletcher and Munson curves and also the Robinson and Dodson curves show this clearly. That is the reason why Graphic eq ie: 1/3 octave will not work. Same with Parametric which controls not only boost/cut, variable freq but Q=the broadness of the affected curve. These can not provide variably freq adjustment based on SPL(volume) levels. In other words is complicated get professional help!!
In regards to hearing aid and limited dynamic range. I would go with 300B
triode powered types they will limit with nice smooth euphonic heavenly second order harmonic distorion. 845 triodes have more overhead but look funny sticking out of your ears. You decide!!
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Roland,
Much of the delicacy of tube amps will be lost on the hearing impaired. (I'm not being nasty here.) Because their HF response is much reduced their perception of distortion products from the amp or speakers is also reduced. So an amp with the third harmonic at -60dB will be similar to one with the harmonic at -70dB for someone with 10dB of HF loss. Many people have much more than that.
The reason I say this is to encourage people with hearing loss to spend more of their money on effective processing and less on esoteric amplifiers, the subtleties of which are probably inaudible.
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Marcus:
You missed the joke!!
Dan had said his hearing aid was dynamically challenged. I suggested he get a 300B tube model hearing aid....that the 845 tube had more overhead but would look funny sticking out of his ears....Ho,Ho,Ho (the 845 is large transmitting triode tube)
By the way I like your cheaper solution to his problem, its a good idea. At worse he can just use a 1/3 octave graphic Eq and correct the deficits at his usual listening volume. He can switch bypass the unit with company around. Quality Graphic Eqs like Clark, White, Altec etc could be used.
YOU HEAR THAT DAN!!! Just kidding again!!
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Marcus:
I'm likeing what I'm reading here, too bad I got rid of the pair of LA-4's I had. Might have been a good start. Obviously this stuff would go in ahead of the bi-amp crossover. I don't imagine that the paralleling of pre-outputs would present much of a problem with most pre's. The set up would take a SPL meter I think. Don't have one.
I like it.
Fellers: I definitely got the tube hearing aids bit. I've even fantasized about some kind of backpack battery unit to take to chamber concerts with a couple of EL-84.....anyway, Marcus' admonition to concentrate on the processing end brings up a couple of points. As much as I would like a pair of PSE 300B monoblocks the fact remains that I don't think I could tell the difference between them and a pair of PP 6550's. If I could audition them it would be nice. Would take a trip to the States to do it though. I guarantee that I can tell the difference though between the PP 6550's and an Adcom GFA535. Don't know why just can. The second point is that all that processing is bound to degrade things, but I suppose it's just too late (hearing wise) for the minimalist approach. All of this will of course take time. My work here in Alaska is very seasonal and right now we're broke....patience is the virtue I can't wait to aquire. I'm still waiting for my 604-8K's to arrive from L&M trading. I'll be pushing them with the Onkyo for now.
Dan
Fairbanks...+10F today.
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Roland,
You got me on that one.
This hearing loss thing is interesting. I have a friend who has worked in many high noise industries in the past and he has quite noticeable hearing loss. I might try the system on him.
Dan,
The LA4s would have been perfect.
There are older Altec and UREI EQs going really cheaply on ebay. Especially the UREI 527 or 539. The 539 is cut only, but that would still work OK, you just reduce the bottom end. The 527 is quite noisy with it's LM301 ICs. I changed them to TDA1034 and dropped the noise by about 20 dB!! The 539 is a lot quieter, they made the cut only ones quieter as they were for studio use.
I have a couple of Altec 1650 EQs and would recommend them also, cut only again.
All of the above EQs are passive (ie. have inductors).
There are active (IC filter for each band)types also:
The Altec 1653B
The Altec 1652A would also be good. It's only 10 band, but that is probably fine for your application
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Dan:
Aside from being a serious Altecophile, I practice medicine once in a while. I say this because the causes of hearing loss are many. A specific diagnosis needs to be made and ruling out many potentially curable problems needs to be done ASAP. I presume you have gotten worked up and the diagnosis is sensoryneural (nerve) hearing loss secondary to chronic noise exposure. If so no problem but if no diagnosis has been made yet YOU NEED WORK UP.
Best wishes
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Roland:
Thanks and yes to all of the above. One of the few really great things about my job is the insurance. I am told though, because of the inherited tendency to hearing loss, it will continue to erode somewhat. Hearing protection in any sort of noisy environment is mandatory. I've informed my wife, for instance, that I cannot run the vacuum cleaner. http://www.hostboard.com/forums/
Dan
Fairbanks
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Hey Now, although not a specific Altec subject, I believe hearing is important to all of us in audio, so I have taken the time to consult a friend of mine who knows a bit about hearing and such about this subject, as follows:
Info re hearing loss and hearing aids follows:
Questions and concerns regarding hearing loss, hearing aids, and dynamic
range are most worthy of discussion, and this topic may be more complicated
that what a lot of readers realize.
While studying Audiology as a grad student (my stepping stone to becoming a
"hearing scientist"), I worked as an extern at a local VA Hospital. One
common questions was, "Why can't they make hearing aids sound better?"
Most wearers were more concerned about the tonal quality (in lieu of
dynamic range restrictions), but the answer addresses both concerns. In an
attempt to answer their question, I used an analogy of visual impairment
and eyeglasses. If an individual has visual loss resulting from sustained
exposure to bright light (e.g., the sun), the damage will most likely be to
the eye's retina, and even the thickest eyeglasses won't be of much help.
And shining more light into this individual's eye wouldn't do much to
increase visual acuity either; it would probably hinder it. Even if a lens
can focus a sharp image on the retina, the visual distortion is internal to
the person (and their brain), thus making visual processing difficult.
Similarly, about 95% of the individuals with hearing loss have some form of
damage to the cochlea (the organ for hearing), and the distortion they
experience is internal. About 5% of individuals have a "conductive"
hearing loss. Conductive hearing losses can result from disarticulation of
the ossicles (middle ear bones), rupture of the tympanic membrane
(eardrum), blockage or fluid in the middle ear (e.g. otitis media which is
common among young children), and other causes. For these individuals, a
hearing aid that simply makes sound "louder" would be highly effective
because they wouldn't experience internal distortion or dynamic range
limitations (other than normal limitations).
Let's return to the topic of sensorineural hearing loss because this is
what most individuals experience as a result of noise exposure (which can
be very insidious), age, disease, and other causes. We all realize that
soft sounds need to be made louder in order for hearing-impaired
individuals to hear them. What most folks don't realize is that loud
sounds can be a lot more irritating (or even painful) to persons with
hearing loss. The sudden and rapid increase in loudness (note that
loudness is a perception, not a physical measure) to hearing impaired
persons is known as recruitment of loudness. This presents a problem to
Audiologist (or anyone qualified to fit hearing aids) because soft sounds
need to be increased in intensity (or "volume"), while loud sounds need to
be reduced in intensity. This, of course, requires compression circuitry
within the hearing aid. Peak limiting circuitry is also added to put a
ceiling on the maximum sound pressure level (SPL) that a hearing aid (HA)
wearer would experience.
A reduction in dynamic range probably isn't the culprit that makes music
listening less enjoyable for HA users. Years ago I had a lot of
involvement in radio transmitter design for an FM station. To my
knowledge, most radio broadcasts have very limited dynamic range (2 dB?)
plus extremely effective peak limiting circuitry (this is needed to protect
the transmitter). Despite the reduced dynamic range and potential for
limiting-induced distortion, FM broadcasts can be enjoyable and of good
fidelity. A mistuned station, however, can be quite irritating at any
volume level. I can't state that this is how hearing impaired individuals
perceive sound, but it is known that much of the distortion they perceive
is generated at the cochlear or "nerve" level. Even the most advanced
hearing aids (using digital signal processing) cannot correct for this
internal distortion. Hearing aids have improved vastly over the years,
but the advances aren't a result of "higher fidelity" transducers or
circuitry. Advances will come about as a result of re-shaping or modifying
the acoustical signal in ways that allow the wearer to hear and understand
speech (and enjoy music). Note that I used both "hear" and "understand" in
this last sentence: Just because a person hears a sound doesn't guarantee
that the sound makes sense. Central auditory processing is a topic of its
own, but its safe to say that auditory processing is compromised as a
result of sensorineural hearing loss. At present, nearly all hearing aids
are designed to improve communication and, consequently, are designed to
enhance speech but not music.
I know one musician who incurred sudden hearing loss as a result of
meningitis. This person is also an astrophysicist who does a lot of signal
processing and is knowledgeable in electronics. Because of the sudden
loss, he was able to accurately remember how sounds should sound compared
to his current hearing disability. During the past two years or so, this
person has worked on a better hearing device for musicians. Even with
high-fidelity earphones, signal sources, and a powerful signal processing
system (much larger than what can presently be fit into a hearing aid),
this person admits that re-creating "live" music with a hearing loss is a
difficult task.
It is very important to mention that hearing loss varies from person to
person, and that there's no single "best" hearing aid. Programmable
hearing aids allow adjustments (usually filter settings) to be
custom-tailored to each person. A lot of "fine-tuning" requires feedback
from the wearer; matching the high- or low-pass filter settings to match an
audiogram (the chart that shows the degree of hearing loss as a function of
frequency) doesn't always give the clearest sound. Adjusting compression
isn't easy either, as different situations require different settings.
We're usually happy with a new pair of glasses, as these don't take time to
adjust; this usually isn't the case with hearing aids.
Note: No references cited for the above info; wrote this off the top of my
head while at breakfast this morning. I believe the info to be accurate
(minus any typos).
Eric L. Carmichel
ELC Audio Engineering
www.elcaudio.com
I know a lot of info to take in but I do hope you all found it interesting, now excuse me while I go play with my Beryllium/Copper screwdrivers and diaphragms.
-Michael Edwards http://www.hostboard.com/forums/
