Why speaker become sounding compressed, when played too loud?

[darw82]

Hi,
Why most of speaker become sound compressed or "break" when played too loud? of course other than clipped source problem.

1. Is it because of the material?
2. Generally, which one of the following material allowing us to
drive the speaker (mid woofer) really hard?
- Paper
- Kevlar
- Rigid carbon
- Polypropylene

Thank you.

[SheldonD]

compression occurs as the voice coils heat up.

this reduces the current because of increased resistance

If small gauge wire coils used this could also be happening.

[AndrewT]

Hi,
the combination of light weight and fibre construction makes paper very good for high sound pressure levels.

It is used almost exclusively in PA duty.

Small voice coils may be more susceptible to compression than big VCs.

[chops]

One of the joys of using high efficiency PA drivers for the low end and compression drivers/horns for the top end. For home use, I doubt you would ever get compression from these types of drivers. At least I never have.

[Brett]

Originally posted by chops
One of the joys of using high efficiency PA drivers for the low end and compression drivers/horns for the top end. For home use, I doubt you would ever get compression from these types of drivers. At least I never have.

I agree. The OP's issue is likely small, low efficiency 'phile drivers that are being pushed very hard to get any sort of decent SPL.

[AndrewT]

Originally posted by Brett
....... low efficiency 'phile drivers........

The low efficiency is a direct trade-off for wide bandwidth. If you want loud, you use lightweight cones and accept the narrow bandwidth.
If you need wide bandwidth you MUST SACRIFICE something and loss of efficiency is much easier to sell than enormous size and multiple drivers.

[Brett]

Originally posted by AndrewT
The low efficiency is a direct trade-off for wide bandwidth. If you want loud, you use lightweight cones and accept the narrow bandwidth.
If you need wide bandwidth you MUST SACRIFICE something and loss of efficiency is much easier to sell than enormous size and multiple drivers.

I'm well aware of this, but I know where I prefer the compromises. If the wide BW is it so you can have a small, inefficient, dynamically constipated two way, then I'd rather use my STAX 'phones.

[chops]

Originally posted by AndrewT
If you want loud, you use lightweight cones and accept the narrow bandwidth.

Well, we'll see just how "narrow" the bandwidth of high efficiency PA loudspeaker drivers really are once I get my Usher D2 clone project underway. If mine measure anywhere near the D2's, I should be getting down into the low 20's, high teens, and pretty much flat up to the xover point of 600-760Hz.

Granted, I'll have FOUR 15" drivers in FOUR 8.3cf ported enclosures tuned to 26Hz to do it, but I'll also have all the dynamics in the world with 98+dB efficiency per channel.

[auplater]

Originally posted by chops



Well, we'll see just how "narrow" the bandwidth of high efficiency PA loudspeaker drivers really are once I get my Usher D2 clone project underway. If mine measure anywhere near the D2's, I should be getting down into the low 20's, high teens, and pretty much flat up to the xover point of 600-760Hz.

Granted, I'll have FOUR 15" drivers in FOUR 8.3cf ported enclosures tuned to 26Hz to do it, but I'll also have all the dynamics in the world with 98+dB efficiency per channel.

Sounds kinda serious...

Is this for your bedroom system?

John L.

[Cloth Ears]

Originally posted by AndrewT
The low efficiency is a direct trade-off for wide bandwidth. If you want loud, you use lightweight cones and accept the narrow bandwidth.
If you need wide bandwidth you MUST SACRIFICE something and loss of efficiency is much easier to sell than enormous size and multiple drivers.

Like Lowther drivers? DX2 30Hz-20kHz @ 97dB/W/m.

But, you're right about sacrifice, even the cheap ones will set you back $500 each.