Understanding driver SPL ratings?

[paradigm]

Question:
The specs of a driver list a SPL of 90dB/2.83v/1m. Is this a measurement of the driver in free-air? If so, is it correct to say that the same driver in an enclosure will yeild a higher SPL with the same reference input voltage taken at the same 1m distance?


Therefore, in actuality, when placed in an enclosure and placed near wall/floor boundaries, I will achieve a higher SPL at that given voltage?

[ocool_15]

I'm not 100% certain this applies in all cases but:
Its done at a midband frequency on a infinite baffle. I think I've seen 1000Hz used or possibly an average. There will be some baffle affects around this range in a typical speaker. The environment around the speaker will have some affect/ripple so you could be louder at least at some frequencies.

[JustinG]

Question:
The specs of a driver list a SPL of 90dB/2.83v/1m. Is this a measurement of the driver in free-air? If so, is it correct to say that the same driver in an enclosure will yeild a higher SPL with the same reference input voltage taken at the same 1m distance?


Therefore, in actuality, when placed in an enclosure and placed near wall/floor boundaries, I will achieve a higher SPL at that given voltage?

In the bass region if placed next to walls you will get bass reinforcement, so you could get high SPL, but for the most part sensitivity will be lower because of baffle step loss. I can't explain baffle step as well as others just google it.

[Æ]

Question:
The specs of a driver list a SPL of 90dB/2.83v/1m. Is this a measurement of the driver in free-air? If so, is it correct to say that the same driver in an enclosure will yeild a higher SPL with the same reference input voltage taken at the same 1m distance?

No, the industry standard way of measuring drivers (IEC) is on a big flat baffle.


Therefore, in actuality, when placed in an enclosure and placed near wall/floor boundaries, I will achieve a higher SPL at that given voltage?

For the inverse reason that a narrow enclosure pulled away from the rear wall needs baffle step compensation.

[billfitzmaurice]

Question:
The specs of a driver list a SPL of 90dB/2.83v/1m. Is this a measurement of the driver in free-air?
It's in a standard baffle (IB) anechoic half-space.

Therefore, in actuality, when placed in an enclosure and placed near wall/floor boundaries, I will achieve a higher SPL at that given voltage?That depends. The quoted SPL is infinite baffle, so with the average woofer in a vented box you can at best expect that SPL to the vicinity of Fb. Depending on placement you can get up to 12dB more, but that's rare.

you could get high SPL, but for the most part sensitivity will be lower because of baffle step loss.
In most cases someone looking for boundary reinforcement does so with a subwoofer, and so long as the baffle is less than 1/4 wavelength from the boundary there is no baffle step. At 100 Hz that's 2.8 feet, so it's not difficult to achieve.