Selecting Speaker For Low Volumes??

[makinrose]

Hi everyone!  I'm interested in hear what opinions about what speakers work best for using Power Scaling and playing at low volumes.  I've had mixed success selecting speakers for this task.  I find that many speakers seem to have "minimum volume" needed to get them to start sound like themselves. It isn't too loud for stage but too much for practicing alone.   Some speakers especially the Celestion speakers I've tried sound sluggish at low volumes.  I've had more success with mid powered American voiced speaker like vintage C12Ns but of course that speaker doesn't work for all styles or amps.  What speakers do you guys have success with when using power scaled amps at lower volumes?  Are there certain specs I should be selecting for?  Any insight would be helpful!  Thanks!

[K O'Connor]

Hi Guys

Yes, speaker drivers seem to have a minimum loudness before which they sound "full". However, once I started using the detuned cabinets I found that the same drivers had a fuller sound at a quieter level.

It is well-known that horn-shaped drivers have a throat resistance that must be overcome, and this presents a problem for quiet listening. However, horn midrange and tweeters tend to be used in systems intended to be played loud, like PA systems, so the threshold of output is not an issue.

Dynamic drivers like those used for musical instruments likely have some resistances to overcome, too. The voice coil is inductive, although its value is quite low. Still, it will respond like any other inductor and try to maintain whatever state the current through the coil is at any given instant, meaning that it will create a current to resist changes to the current. An initial input will be resisted by an opposing current; magnetically-stored energy will be released to maintain the flow as the stimulus diminishes. This really works counter to the instantaneous response that would be ideal for a speaker, and the effect would be greater for higher currents than lower ones. Maybe it is proportional, which might make it audibly as bad at all SPLs?

Back EMF from speakers is a known problem.

Air resistance keeping the cone in its rest position is another form of resistance. A sealed cabinet would exhibit this tendency more than other box designs and would be maximised in cabinets that are very small - ones that are just big enough for the driver to be mounted in. Critically-vented cabinets would also have this problem except at the vent resonance. Open-back cabinets and detuned cabinets would have no air resistance for the cone to work against.

I am not a speaker expert, but for the application of playing very quietly I believe the cabinet has more influence than the specific driver.

[makinrose]

Hi Guys

Yes, speaker drivers seem to have a minimum loudness before which they sound "full". However, once I started using the detuned cabinets I found that the same drivers had a fuller sound at a quieter level.

It is well-known that horn-shaped drivers have a throat resistance that must be overcome, and this presents a problem for quiet listening. However, horn midrange and tweeters tend to be used in systems intended to be played loud, like PA systems, so the threshold of output is not an issue.

Dynamic drivers like those used for musical instruments likely have some resistances to overcome, too. The voice coil is inductive, although its value is quite low. Still, it will respond like any other inductor and try to maintain whatever state the current through the coil is at any given instant, meaning that it will create a current to resist changes to the current. An initial input will be resisted by an opposing current; magnetically-stored energy will be released to maintain the flow as the stimulus diminishes. This really works counter to the instantaneous response that would be ideal for a speaker, and the effect would be greater for higher currents than lower ones. Maybe it is proportional, which might make it audibly as bad at all SPLs?

Back EMF from speakers is a known problem.

Air resistance keeping the cone in its rest position is another form of resistance. A sealed cabinet would exhibit this tendency more than other box designs and would be maximised in cabinets that are very small - ones that are just big enough for the driver to be mounted in. Critically-vented cabinets would also have this problem except at the vent resonance. Open-back cabinets and detuned cabinets would have no air resistance for the cone to work against.

I am not a speaker expert, but for the application of playing very quietly I believe the cabinet has more influence than the specific driver.

I agree that open back or detuned cabs sound better at low volumes but do think the specific speaker has a lot to do with the effect on tone at low volumes.  I had not thought about the inductive properties of the voice coil.   Very interesting....

I'd been thinking it had more to do with the physical characteristics such as the weight of the cone, stiffness of the spider, type of surround the speaker has and magnet size. My general experience had been that lighter assemblies tend to sound fuller and more like themselves at lower volumes.  Of course, these same speaker types are less efficient and have much less dynamic linearity, so they tend not to work well at higher volumes, have less low end, and don't usually handle distorted tones as well.     I'm going to inquire with a speaker re-coner that I trust to see if he has any insights.  I'll report back.....