Confused About Speaker Design and Hearing Loss

Being 60+ years old, I have lost hearing above about 12kHz. I have searched this forum on this subject and there are many posts about hearing loss with age, but no apparent conclusions about the effect on speaker design.

The holy grail of audio seems to be flat response to 20kHz or beyond. But if hearing above 16kHz is very limited, do we need to design out to those limits? If I instead target flat response out to 15kHz won't my design task be easier, less costly but with equal sounding results?

Or are there artifacts or harmonics that are within my range of hearing that will be lost as well?

Lindsay
 
Well, I can distinguish a primary tone up to right around 16khz. In my rig, I have a nearly limitless ability to EQ digitally, and I've played with really pumping up the top end to see what effect it has. The highest frequency I can set a shelf boost is 16000 Hz, and generally I don't hear any difference until I've set at least +6dB on that, at which point I start to hear more "air", meaning the sound stage seems to open up a bit and the music gets a bit more realistic. I can't actually distinguish what's going on with my ears, but the music becomes more pleasant. That usually caps out in the +12-18dB range, after which the sound quickly shifts from "better" to strident, glaring and really quite flat (not to mention a serious pain to listen to. The exact amount that works well for me depends on my signal chain and what device I'm listening too. Of course, in my experiments it also works just fine with devices that aren't supposed to be able to handle those frequencies, like my Pioneer B20s that are supposed to cut out around 16kHz, just as well as my Grado SR-80 headphones, so I'm not exactly sure what's going on.

What I'm sensing though, is that you could get along with any of the 8" or larger "full range" drivers we talk about around, and probably get away using them straight, no supertweeter like most folk use. Another point to add is that, unless you are the only one who will ever listen to your designs, it wouldn't hurt to at least pay them a little service, like a $2 piezo crossed really hight ;)

Do you have anything in particular in mind at this juncture?

Kensai
 
Kensai,

Thanks for your response. Your hearing is clearly better than mine. I have boosted the high frequencies using the equalizer on my PC and I can boost the 16kHz control to the maximum and I hear no difference.

I need speakers for the bedroom so they will not be in a large room. I looked at the metronome (72 inches tall with the Audio Nirvana 10 inch speakers) and they will probably not pass the wife acceptance factor. I like good bass response and either need to take that into account in the main speakers or consider adding a sub woofer.

I was thinking of trading high end response for low end response hence my initial question. I do like the idea of a full range speaker as I think it will provide better sound than a two way or three way speaker.

I had looked at the Common Sense Audio Web site and was considering using one of their design plans with the Lowther PM6C. Then if there is insufficient bass I could add a sub woofer.

But I am open to anything. I am good with wood working, but have no experience designing speaker cabinets. I have seen the programs online that will calculate speaker enclosure dimensions, and could go that route if that is the best way to go. But if someone has a proven design then I could avoid any potential mistakes.

Any suggestions are appreciated.

Lindsay
 
LHMAudio said:
Being 60+ years old, I have lost hearing above about 12kHz. I have searched this forum on this subject and there are many posts about hearing loss with age, but no apparent conclusions about the effect on speaker design.

The holy grail of audio seems to be flat response to 20kHz or beyond. But if hearing above 16kHz is very limited, do we need to design out to those limits? If I instead target flat response out to 15kHz won't my design task be easier, less costly but with equal sounding results?

Or are there artifacts or harmonics that are within my range of hearing that will be lost as well?

Lindsay

Lindsay, I too am an old fart at the young side of sixty, and have what is called bilateral high tone deafness. I am a combat veteran, and got my injury in the military. Too many tank guns and M-16's high pitch crack. Also, I use a compressor in my business, and I wear stereo headphones when I use my staple gun, because the noise of the gun's blade, striking the wood as it drives the staples into the wood, bothers me.

But just because you have a hearing disability does not mean that you are unable to pick up high frequency signals. Inside the inner ear, and also within the cochlea, are tiny hairs, called celia, which act as tuning forks for the different pitch of all sorts of frequencies. Every frequency has celia of certain length and thickness, which generate different frequencies. These frequencies are, in turn, amplified as they move up the auditory nerve to the brain.

As you experience age, or trauma due to loud noise, the celia of certain frequencies are damaged. Over time, they will shrivel up and die. Many, however, will not.That is why a hearing aid will be able to amplify a certain frequency, and you will still be able to hear it. And that is because some of those dedicated celia for that frequency are still functioning. If they were all dead, you would not be able to hear ANY frequency, even with amplification.

Today's digital hearing aids are becoming very sophisticated, in that the number of dedicated frequencies to amplify are increased. Today it is common to see digital hearing aids that have over fifteen or twenty different frequency stages. In a few years, it will be almost unlimited. Perhaps the future ones will be able to amplify sounds every ten cycles, who knows.

But the neat thing is that science is now hot on the trail to manipulating genes in certain animals and regrowing these celia. In other words, by regrowing a full crop of celia, you would be able to hear like you could as a child. And it may be possible to even tailor the celia to grow and pick up frequencies below or over what humans can naturally pick up. Amazing!

I am now at the point where I really should have hearing aids put in my ears. Fortunately the VA will provide them for me, and better yet, give me all the batteries I need, for the rest of my life.

As for hearing, you can still discern certain frequencies that you may not think you should. And with practice you can discriminate more than you could without practice. for instance I can definately tell differences with many of my receivers. My Marantz is about as mellow as you can believe. Yet my Bogen tube receiver, which I am using right now, has a most sublime sound, yet is is as clear as a bell, more so than my Sansui 2000X that I also use with my computer.

So while you may be a little bit challenged, you are not without ability. The best thing to do is shoot for the best, listen carefully, and enjoy the best quality you can provide. I would still try to create a set of loudspeakers that cover the entire spectrum, because chances are you can still hear some of it, and with hearing aids, the possibilities are even better. That's what I would do.
 

Bobken

Member
2002-12-23 11:22 pm
UK
Hi LMH,

I am in the same age-group as yourself, and have played around with speakers and X'overs for nearly 50 yrs., but my experiences and advice virtually mirror those of Kensai.

Regrettably, I cannot hear pure sine-waves in excess of 10K-ish now when on test, but disconnecting Townshend Super-tweeters from my system which don't give anything much by way of an output below 20K Hz, gives an immediate 'loss' to me when listening to my audio system.

Amongst other effects, there is a loss of focus of sounds which I miss, so 'don't do yourself down' here, even though you might not think that this matters with your age-related deficiencies.

Regards,
 

ronc

Member
2003-03-08 2:22 pm
but disconnecting Townshend Super-tweeters from my system which don't give anything much by way of an output below 20K Hz, gives an immediate 'loss' to me when listening to my audio system

True here too. When i added the ribbon tweets to the 208 there was an immediate increase in resolution and a bit of high frequency response beyond my normal 12 Khz limit.

Happy New Year to all authorized personnel.

ron
 
John L

Thanks for the detailed reply. I was not aware that hearing aids amplified only certain frequencies. What is the highest frequency they amplify? I would be surprised if it were over 10kHz. I live in Arizona and there is a lot of bioengineering activity here. Growing new celia is very appealing. I just hope I live long enough to see it!

Bob, Ron,

I did a little looking on the Web for the Townshend Super-tweeters. It's hard to believe you can hear a difference with them. But if you were willing to shell out $1,600 for them then they must contribute to the sound of your systems. I have often wondered about reproducing square waves with a speaker system. In effect the square wave has a dv/dt that is infinite and would require the highest frequency response possible to properly reproduce, so I suppose it is possible to hear the difference.

In any case thanks for straightening me out of this topic.

Lindsay
 
LHMAudio said:
John L

Thanks for the detailed reply. I was not aware that hearing aids amplified only certain frequencies. What is the highest frequency they amplify? I would be surprised if it were over 10kHz. I live in Arizona and there is a lot of bioengineering activity here. Growing new celia is very appealing. I just hope I live long enough to see it!



I am not personally intimate with digital hearing aids, since I have not gotten to the point where I am in the process of obtaining them. I always make a habit of researching things before I get ready to do something like that.

However, I would guess that the digital aids are programable to work at just about any frequency they choose. The shortcoming is based on the number of frequencies the integrated circuit is set up to handle. Obviously the more channels it can work with, the more expensive. I would suspect that in a few years, you will be able to get a hearing aid that can amplify fifty to one hundred different frequencies, at a reasonable price.

Let's not forget Moore's Law.
 

Bobken

Member
2002-12-23 11:22 pm
UK
Hi Lindsay,

To set the record straight, I didn't pay for these Townshend Super-Tweeters, as I did some work for someone in the audio trade and this was part of the deal on offer.

However, I had listened to these S-Ts before agreeing the deal and would certainly consider their purchase if I didn't already have these S-Ts, as their effect is worthwhile in my opinion. I did not have them to listen to when my HF 'threshold' was much higher, but my wife's upper limit is a lot higher than mine is now, and she appreciates the improvements/differences similarly

Interestingly, the 'ordinary' tweeters in my system, and which these S-Ts are used together with, have a virtually flat response to past 20k Hz, as I have measured them in my listening room. Also, these S-Ts have an amplitude adjustment which ranges from '0' to '8', and I never use settings above '3' or '4', but mostly (as now) they are set merely at '2'. Much above this, they start to 'dominate' the HF and begin to sound less good, but of course my main drivers are relatively low in efficiency, and I am an extremely critical listener with still very high acuity within my existing range.

What surprises me about this, though, is the fact that I can immediately tell these differences even though there is little S-T output below 20k Hz, and on simple sine wave tests, I cannot hear anything much above 10k Hz!

You mention square-waves, and this is interesting as, of course, one needs to have good HF response in the electronic circuits of any system to reproduce such wave-forms well. In the course of speaker and amplifier developments for around 40 yrs., I have tried many different kinds of experiments, with one of them being listening for some weeks with certain drivers disconnected in my 'usual' 3-way systems, and sometimes even listening to 1 driver alone. I find that this helps when identifying some effects (characteristics) peculiar to certain drivers, which although I have the equipment, I have not been able to measure adequately.

These effects are not amplitude-related, which can be readily measured and quantified, but are the results of the kind of construction and materials used in the drivers concerned. When other drivers and their associated X'over components are used in addition, I find that this tends to be a distraction and confuses these issues, and it is harder to achieve what I wish for here.

If ever you try this, you will doubtless find that on disconnecting a tweeter (in my case currently the lower -3dB point being around 4k Hz) this will have a very marked adverse effect on bass sounds like kick-drums, the initial 'strike' of which is at a high frequency although the main body of sound is maybe only at around a few tens of Hz. The entire sounds in the bass regions go 'soggy' or 'very woolly' for want of a more suitable expression!

It is for reasons such as these (and others which I haven't gone into here) that I suggested before that you should not 'do yourself down' merely based on known age-related hearing losses.

Regards,
 

OzMikeH

Member
2007-03-18 9:22 am
LHMAudio said:
Kensai,

Thanks for your response. Your hearing is clearly better than mine. I have boosted the high frequencies using the equalizer on my PC and I can boost the 16kHz control to the maximum and I hear no difference.

.........

I was thinking of trading high end response for low end response hence my initial question. I do like the idea of a full range speaker as I think it will provide better sound than a two way or three way speaker.

........

Lindsay

If you use the equaliser or software volume control on your PC you will lose that fullrange magic. I've started paying attention to the microdynamics in music and have progressed from 256k MP3 on internal sound card with software volume and EQ through to buying an ASIO compatible soundcard, WAV at full sample rate and a bit perfect output from the PC and moving the volume control to the analog domain. Each step has revealed greater detail in the music. Now I can hear the difference between speaker cables, which, as an electronics technician, I thought was complete rubbish and Audiophoolery. I use an Edirol UA-1EX sound card (cheap at US $100) with a modified USB extension so it has it's own 5V supply. I use that with Winamp ($free) with the preferences set for direct output.

Above all please dont use software equalisers and volume control, it's almost as mad as using MP3 if you're really into that fullrange sound.

I'm thinking for a bedroom system you should consider a smaller fullrange with a tall, skinny box (cant remember the name but it has the top panel at 45 degrees) It looks like it's about 6 inches square.
That way you get the detail and high end of a smaller driver with the cabinet that can deliver the some bass at lower volumes.


Edit: I meant Bad as using MP3, not Mad, I was about to correct it but Mad is actually more appropriate.
 

ronc

Member
2003-03-08 2:22 pm
I'm thinking for a bedroom system you should consider a smaller fullrange with a tall, skinny box (cant remember the name but it has the top panel at 45 degrees) It looks like it's about 6 inches square.
That way you get the detail and high end of a smaller driver with the cabinet that can deliver the some bass at lower volumes.


Zigmahornet.

And again, some bass is subjective, Its basically an out of date design that the pipe length is tuned .707 x the Fs of the 103. I could tune a 3" driver to go lower, at the expense of a wild FR curve. ( something like Bo.. with their clock radios)

ron
 
Lindsay,

I too have recently joined the free-bus-pass brigade.

Over many years I have read similar discussions. The general conclusion is always the same as that reached here - listening to sine waves is just macho stuff for the kiddies of 50 and younger; you can still hear extra resolution in the music if your system is capable up to, and even above, 20kHz.

I second Ron's suggestion of the tall, narrow format as the best compromise.

Andy
 
OzMikeH,

I only used the PC equalizer to test my hearing. It is normally not engaged. I use Foobar with ASIO4All out to the Alien DAC which was a DIY project posted on head-fi. I normally leave the PC volume on full and control the volume with my preamp.

I found this design for a speaker system yesterday and thought it looked pretty well researched. http://www.zaphaudio.com/ZD5.html

I am not sure if you would call it full range since it has a tweeter, but it seems like a good performer with good bass potential with a vented enclosure.

I had also looked at a bipolar speaker called Ambiance in AudioExpress several months back, but I was not sure that it would perform well. The speakers in that design were angled up, but I am not sure if the angle was 45 degrees. My main speakers are Martin Logan and I like the bipolar sound.

Without question a small footprint will help with the Wife Acceptance Factor. Along those lines I had also looked at this transmission line design:

http://www.t-linespeakers.org/projects/tlB/index.html

Ron, I took a look at the Zigmahornet and that will definitely pass the WAF. I will do more research on it. I would probably add a subwoofer to the system as I do like bass.

Andy, Thanks for your comments. I am convinced that I need to go for the full 20Hz to 20kHz or better or I will be disappointed.

Any other advice on what designs to look at would be appreciated.

Lindsay
 
OzMikeH,

I've been through that whole gambit as I was coming up through AVSForum and then Head-fi.org. I'm using an E-Mu 0404 sound card, ASIO out for all music and for my line inputs (though I'm forced to use WAVE out for DVD and other PC sounds).

I never allow a software volume control to even exist as the quality degradation is instantly noticeable. I had a PreSonus HP4 headphone amp that I used as a preamp for my speakers, and I have since determined that it was really bad, not just as a preamp but as a headphone amp, but it was far and away better than software volume control. I found using the volume knob on my JVC Hybrid Feedback amp (the core of a small old shelf system) was much better, still, and the knob on my new SI T-Amp Gen2, while maybe not better, isn't a step back and let's amp's superior sound shine through just fine.

I do all of my digital EQ in the E-Mu's PatchMix application which is a Pro level bit of software, and while I can't directly compare it to any analog EQ (as I've never owned any), I can compare it to the EQ available in dozens of other playback softwares and against not having PatchMix active at all. Against any other software EQ, PatchMix wins, hands down. You turn on any other sort of software EQ and SQ drop like a rock, instantly, no questions asked. If you compare PatchMix w/EQ, PatchMix w/o EQ and no PatchMix, the better sounding one is always the one running the appropriate EQ. The fact that this happens before the DAC leads me to believe that this is the cleanest way to do this. Of course, the components in the 0404 aren't the best in the world (what can you expect for $80 worth of kit that sitting inside a PC case?), but for the money is unbeatable, unless you find a newer, better card that is now around the same price that gives comparable capabilities with better components/build quality.

So, yes, Windows' K-Mixer is the enemy, so never use the volume controls in your software if you can avoid it (and if you can't shut them off like in WinAmp, at least leave them at 100%). ASIO out with a compatible card is your best friend. Music archived in a lossless format (APE, FLAC, etc.) is the only way to go. If you have to playback MP3 format (I have tons of music that can't be had in any other format), use the in_MAD.dll decoder in WinAMP with the settings maxed (its a very nice upgrade from any default decoder I've ever heard).

Kensai
 

ronc

Member
2003-03-08 2:22 pm
second Ron's suggestion of the tall, narrow format as the best compromise.

Maybe i wasent clear.

You have to have wave support either through the BW of the cab to the baffle or have a baffle step circuit to compensate.
An easy answer was to increase the area of the baffle to "fill in" the missing wave support. Hence the suprabaffle (name coined by Dave).

In the old days of huge speakers with lots of frontal area, this wasent a problem. However in these days of ppl likeing tall skinny( like my lady i like the other direction) speakers , there has to be a baffle step circuit which can also help balance a rising response done correctly.

Give me a full robust larger speaker (again like my lady) that has full performance (no statement here).

ron