Hi.
I have been giving thought as to how I might be able to judge a good speaker without listening to it. My first thought was that the more resistance the cone has against the coil, the more prone it is to error. However I am still not sure. Perhaps more is better if it acts as feedback through the coil. Also, the more resistance, the less it is prone to oscillation.
Also, if the cone material is too flexible, the speaker would lend itself to uneven frequency response and sound dispersement vs. response due to the cone flexing. If the speaker's frame is not built rigidly, the speaker would be subject to ringing/rattling which would cause problems for bass and also possibly with percussion instruments with sharp sounds.
Since one can not tell everything about a speaker at first glance, I am speaking strictly technical. Listening is usually the finest test but one does not always get the chance... So I am asking strictly in the sense of what makes a speaker accurate (and/or not "cheap") and not so much as far as its "character".
Thank you,
- keantoken
I have been giving thought as to how I might be able to judge a good speaker without listening to it. My first thought was that the more resistance the cone has against the coil, the more prone it is to error. However I am still not sure. Perhaps more is better if it acts as feedback through the coil. Also, the more resistance, the less it is prone to oscillation.
Also, if the cone material is too flexible, the speaker would lend itself to uneven frequency response and sound dispersement vs. response due to the cone flexing. If the speaker's frame is not built rigidly, the speaker would be subject to ringing/rattling which would cause problems for bass and also possibly with percussion instruments with sharp sounds.
Since one can not tell everything about a speaker at first glance, I am speaking strictly technical. Listening is usually the finest test but one does not always get the chance... So I am asking strictly in the sense of what makes a speaker accurate (and/or not "cheap") and not so much as far as its "character".
Thank you,
- keantoken
It makes sense to me that the less resistance the cone has against the coil, the greater the efficiency. So, if it's easy to push the cone in then it's high efficiency.
Most of the speakers I've had where it was hard to push the cone in sounded decent with the volume up, but any low, delicate sounds could not be heard. When I put other speakers in, I could hear more detailed sound.
A paper cone would be lighter, so it would give higher efficiency than a plastic cone, at higher frequencies. However I am not willing to judge speakers on efficiency alone. Most paper cone speakers I have listened to sounded bad to my ears, maybe I just haven't been around much.
I was listening to some papercones a little while ago and the sound was more detailed and more accurate than my current setup. However I had to concentrate to hear through the "noise" that they seemed to generate. I guess they're just bad speakers.
- keantoken
Most of the speakers I've had where it was hard to push the cone in sounded decent with the volume up, but any low, delicate sounds could not be heard. When I put other speakers in, I could hear more detailed sound.
A paper cone would be lighter, so it would give higher efficiency than a plastic cone, at higher frequencies. However I am not willing to judge speakers on efficiency alone. Most paper cone speakers I have listened to sounded bad to my ears, maybe I just haven't been around much.
I was listening to some papercones a little while ago and the sound was more detailed and more accurate than my current setup. However I had to concentrate to hear through the "noise" that they seemed to generate. I guess they're just bad speakers.
- keantoken
What you are testing for is Kms, which is only one factor in many that determine efficiency.
http://www.diyaudio.com/forums/showthread.php?postid=1665512
http://www.diyaudio.com/forums/showthread.php?postid=1665512
keantoken said:
Its called "low loss"
But if you mean high sensitivity its the other way round
"High sensitivity" is relative, could be anything...but fore home use 93db would be "high"
Fore normal hifi, soft suspended drivers would be preferred, unless you play very loud
But actually its the xo tuning that determines "accuracy", or "speaker precision"
To make things simpler, I would recommend studying the basics that Jordan drivers embrace. He's really done a fantastic job, and have tried various design methods throughout the years.keantoken said:It makes sense to me that the less resistance the cone has against the coil, the greater the efficiency. So, if it's easy to push the cone in then it's high efficiency.
Most of the speakers I've had where it was hard to push the cone in sounded decent with the volume up, but any low, delicate sounds could not be heard. When I put other speakers in, I could hear more detailed sound.
A paper cone would be lighter, so it would give higher efficiency than a plastic cone, at higher frequencies. However I am not willing to judge speakers on efficiency alone. Most paper cone speakers I have listened to sounded bad to my ears, maybe I just haven't been around much.
I was listening to some papercones a little while ago and the sound was more detailed and more accurate than my current setup. However I had to concentrate to hear through the "noise" that they seemed to generate. I guess they're just bad speakers.
- keantoken
by finding out the brand and product number. after that googling for information, like measurements at site below
http://www.audioheuristics.org/measurements/measurements.htm
softer suspension doesn't mean efficient speaker, but higher vas and maybe lower qts.
for examble eminence governor guitar speaker cannot be pushed more than 1mm, with its stiff suspension and 100db+ efficiency.
Effeciency is about motor strenght and weight.
at low bass frequencies, limited by enclosure.
resonance affects behaviour a lot at mid and high bass frequensies, and suspension with mass and cone area define the Fs.
but still, i too would recommend those not so stiff drivers for home hifi, since it imo seems to suggest smallish qts
--> more enclosure options: some high qts drivers cannot be practically applied to refl. cabinets at all, because of their later and steeper rolling of response amplified to boominess at mid/high bass.
I think I might have figured out the problem. When I tested them, I had only twisted the speaker wires on. Figures. A few months ago I wouldn't have believed that something like this could affect sound. Now that I've been messing around more, my feeble knowledge base has grown.
I did test them earlier after 1 day of drying and they sounded better. These things have amazing bass! I think I would describe these as "soft suspension". They must also have large work coils for the extra bass response that my other speakers lack. If I can get the wood I'll try and hack together some enclosures and see what I can do.
- keantoken
I did test them earlier after 1 day of drying and they sounded better. These things have amazing bass! I think I would describe these as "soft suspension". They must also have large work coils for the extra bass response that my other speakers lack. If I can get the wood I'll try and hack together some enclosures and see what I can do.
- keantoken
What I want to know is what to look for if I happen across a speaker and don't have currently available resources such as the internet or equipment or a way to test it. I don't have a lot of money so I must survive off of what I can scrounge from my surroundings. Some obvious things to examine would be:
1: cone resistance
2: frame resonance (tapping or flicking the frame to see if there is rattling or ringing). This can still be fixed with putty, toothpaste, etc.
3: cone material. Kevlars will sound different than papercones, etc.
I'm still not sure if it was loose contacts that were degrading the quality, I will have to test again later.
- keantoken
1: cone resistance
2: frame resonance (tapping or flicking the frame to see if there is rattling or ringing). This can still be fixed with putty, toothpaste, etc.
3: cone material. Kevlars will sound different than papercones, etc.
I'm still not sure if it was loose contacts that were degrading the quality, I will have to test again later.
- keantoken
T/S parameters are a measure of physical and electrical properties, and are the basis for a driver's applicability to a design.
They don't tell you everything.
Joe D'Appolito lists the following, taken as a group for a strong predictor of performance:
On-Axis frequency response, Impulse Response, Cumulative Spectral Decay, Polar Response, Step response Impedance, Efficiency/Sensitivity, Distortion, Dynamics.
You either have to do, or find accurate measurements of some of these, or take the manufacturers word on this. Few publish complete measurements.
Mr. D'Appolito has been designing speakers for over 30 years. And there trade publications specific to the speaker manufacturing.
The conventional voice coil driven transducer has been around since the 1920's and still remains an inefficient device that wastes most of the current given it in heat.
A more efficient driver is better in that aspect, But it is not the only consideration, A manufacturer can optimize extension, or efficiency, power handling, etc, etc.
No free lunch: Notice the drivers with very low Fs have a low sensitivity, the drivers with very high efficiency don't have low Fs.
There are high sensitive drivers made with aluminum, and polypropylene.
Larger in diameter is generally for increased power handling.
Longer Voice Coil is generally for increased Vd ( volume displaced, equivalent to an piston's stroke ).
IMO: A driver is just a pump that can be made in a variety of configurations,. The laws of physics set the compromises you have to accept ( mass, inertia, etc )
Almost. Some speakers are literally manufactured in "bad condition" but will sometimes sound decent if modified. The speakers I'm currently using I got from walmart for 69$. So far they've turned out to be everything I expected of them. All the modifications I've been doing is to the boxes, which are Boston Acoustics A40 Series II (When I got them only one of the original drivers was left, and the surround crumbled on it.). I used electrical tape to put between the new speakers and the boxes after discover that the speaker frames would ring if I tapped on them while they were still in the box. The tweeters still work, but I took out the xo's since the new speakers have tweeters already. Sounds good, as much as possible I suppose. More clarity but there is not so much life in the sound.
I am sure that one can tell a lot about how a speaker might sound simply by feeling how uniform the cone resistance is, what it sounds like when tapped on, etc. Uneven cone resistance would add harmonics to the sound. If I understand correctly, all you want is for the cone to stop before it shoots right out of the speaker and you want just enough resistance that it doesn't self-resonate. The cone surround material should be stiff enough to keep from popping inside out because of the pressure. Then there is the work coil, which might behave differently depending on the shape of the magnetic field. I guess the only way to measure how much this distorts the sound is to just plug it in and listen. I imagine a bad coil can make an otherwise decent speaker meet the landfill, as with many factors of design.
- keantoken
I am sure that one can tell a lot about how a speaker might sound simply by feeling how uniform the cone resistance is, what it sounds like when tapped on, etc. Uneven cone resistance would add harmonics to the sound. If I understand correctly, all you want is for the cone to stop before it shoots right out of the speaker and you want just enough resistance that it doesn't self-resonate. The cone surround material should be stiff enough to keep from popping inside out because of the pressure. Then there is the work coil, which might behave differently depending on the shape of the magnetic field. I guess the only way to measure how much this distorts the sound is to just plug it in and listen. I imagine a bad coil can make an otherwise decent speaker meet the landfill, as with many factors of design.
- keantoken
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