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Bass Cabinet Stuffing
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Author:  chris1973 [ November 28th, 2017, 7:00 pm ]
Post subject:  Re: Bass Cabinet Stuffing

Sorry Sashi!

I have kind of strayed from the original discussion.

I'll start a new thread if anybody is interested in "Sound Intensity"

Chris

Author:  SoundMods [ November 28th, 2017, 7:05 pm ]
Post subject:  Re: Bass Cabinet Stuffing

tomp wrote:
chris1973 wrote:
This all brings up another issue I didn't understand until I had an amplifier with meters on it.I would hope somebody else chimes in on the issue:

We buy speakers that have 100-200 watt capability, and a lot of us buy amplifiers that can exceed 100-200 watts, but depending on your speakers, your actual listening level probably starts hurting before you reach 50-60 watt peaks. Despite this we still seem to think those 200watt specifications, and 110+db simulations we get from them, are of any practical importance.


Chris:

Off the top of my head, three things pop up. First, if you are using meters you may not be seeing true short term peaks. A scope would tell you that. If the amp is really clipping, the clipping behavior of the amp will determine how bad the distortion is. That is why many low power class A single ended amps reach way beyond their rated power. They generally clip in a very benign way. Their actual distortions are not as objectionable.

The second thing is that the drivers (or in rare cases the crossover components) may be distorting. You would have to see the driver distortion vs power input to determine that, Some drivers have very low distortion untill you reach Xmax and then go ballistic. Others have distortion levels that climb more gradually.

The third thing that is often overlooked is your ears. At some point not only does the level sound unrealistic, you can push your ears into a non-linear region.

Anyone else have other ideas?



Ear plugs! :crazy:

Author:  tomp [ November 28th, 2017, 9:55 pm ]
Post subject:  Re: Bass Cabinet Stuffing

Chris:

106 dB at anywhere below 30 Hz is not like the same level at 2 KHz. Look at the Fletcher Munson (now called equal loudness) curves. In addition, having the abiltiy to reach that level at any frequency without distortion helps with dynamic range. I don't listen to that as an average level, but being a Mahler and Shostakovich freak the transients often go over 110 dB where the average is in the 80s. You may be lsitening to a quiet passage and all of a sudden, 7 tymapnies are hit with maximum force. Really wakes you up and if the system can reproduce it the results are much better with less distortion. Definitely adds to the realism.

Tom

Author:  chris1973 [ November 28th, 2017, 10:32 pm ]
Post subject:  Re: Bass Cabinet Stuffing

Equal Loudness Contours!

I knew I saw them before. It will take me into a couple books I haven't looked at for a while.

So the answer actually is "yes".

Thanks Tom!

Author:  Cogito [ December 12th, 2017, 8:37 pm ]
Post subject:  Re: Bass Cabinet Stuffing

Instead of rebuilding a larger bass cabinet, decided to build tapped horn subwoofers first. Current bass cabinet size is just fine for frequencies above 80Hz. If the TH subwoofer behaves like a HT sub, then I will consider a larger cabinet.

Starting with basic woodworking class next month at woodcrafts.

Author:  tomp [ December 12th, 2017, 9:50 pm ]
Post subject:  Re: Bass Cabinet Stuffing

Sounds like a good solution.

Tom

Author:  chris1973 [ December 16th, 2017, 5:04 pm ]
Post subject:  Re: Bass Cabinet Stuffing

Hey Sashi,

Based on the photos of your speakers, in the big room, I have one recommendation for you before you do anything else.

Take the speakers off the makeshift boxes you have them sitting on, and elevate them on four objects near the bottom corners, so that there is an air-space between the bottom of the cabinets, and the floor. This is called "coupling".

You can use any four objects you have handy, like a stack of books or something, but after you hear what the air-space does, you should excperiment with it by adjusting it between about 1" to about 5-6".

It's really cheap, quick, and easy to pull off, before you get involved in the other ideas you are entertaining, but it will change the solund pretty significantly.

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