SPL guidlines for your DIY speaker?

[markusA]

I've been reading up on the general opinion concerning what SPL levels one should design for.
There is however one aspect that confuses me somewhat.

For argument sake let's assume a 90dB average SPL. (I think this should be loud enough for most people?)
Add 30dB max for peaks and we get max 120dB peak SPL.

At what frequencies should you expect the peak SPL?
Should one design the bass for 120dB but the midrange could probably get away with 100-105dB?

What's the thinking regarding max SPL vs frequency?

[Jay]

What!? Are you talking about speaker sensitivity, such as 90dB/w/m?

If your speaker is 90dB but your amp is 5W, it will never be as loud as 200W amp with 80dB speaker. Loudness depends on distance and voltage applied to the speaker (or watt)

When speaker response is made flat, it means it is independent of frequency (in the intended audio band).

120dB/w/m for bass? With crossover? That is rare. We pad down tweeter because woofers in general do not have comparable sensitivity.

[TerryO]

Originally Posted by Jay

What!? Are you talking about speaker sensitivity, such as 90dB/w/m?

If your speaker is 90dB but your amp is 5W, it will never be as loud as 200W amp with 80dB speaker. Loudness depends on distance and voltage applied to the speaker (or watt)

When speaker response is made flat, it means it is independent of frequency (in the intended audio band).

120dB/w/m for bass? With crossover? That is rare. We pad down tweeter because woofers in general do not have comparable sensitivity.

You're correct, but with a 90dB sensitivity speaker, you would need 16 watts to hit 103 dB, while one with 80dB sensitivity would require 240 watts to reach the same 103dB SPL.

FWIW: Most people don't have a real appreciation of how loud even a 90 dB spl actually is.

Best Regards,
TerryO

[planet10]

90 dB avaerage levels is really quite high and pushes you into a range where extended exposure will cause hearing damage,

dave

[TerryO]

Originally Posted by planet10

90 dB avaerage levels is really quite high and pushes you into a range where extended exposure will cause hearing damage,

dave

Absolutely true, although I would have included the word "permanent" to the above.

Best Regards,
TerryO

[graaf]

Originally Posted by markusA

I've been reading up on the general opinion concerning what SPL levels one should design for.

important questions
all answers can be found here: SPL targets for speaker design

have You read that?

[markusA]

I'm working through that thread as I'm writing this.

It would appear my question was a little vague.
Naturally the sensitivity will be the same for both the bass and the mid/high.

I'm talking about the frequency distribution of music. Will the mid-range have to play as loud as the woofer or is the bass generally louder in the recordings? I'm talking about the peak SPL here.
Does the mid-range and treble have as high SPL peaks as the bass?

Acording to the Fletcher/Munson curves we will percieve mid-range as louder compared to the bass given the same SPL.

What are the actual requirements here?

[TerryO]

Originally Posted by markusA

I'm working through that thread as I'm writing this.

It would appear my question was a little vague.
Naturally the sensitivity will be the same for both the bass and the mid/high.

I'm talking about the frequency distribution of music. Will the mid-range have to play as loud as the woofer or is the bass generally louder in the recordings? I'm talking about the peak SPL here.
Does the mid-range and treble have as high SPL peaks as the bass?

Acording to the Fletcher/Munson curves we will percieve mid-range as louder compared to the bass given the same SPL.

What are the actual requirements here?

Markus,

Your first statement is correct for any well designed speaker.

If the sensitivity is the same then they will play just as loud. The recording engineer has already determined the balance that's on the recording.

The Fletcher-Munson curve is, and you mentioned it above, how "we" perceive the balance at different SPL levels. Unless you only listen at a certain, predetermined average SPL level, it's not a good idea to design around the F-M parameters, as it would only have an octave to octave balance at a certain setting. Recordings don't come with a prescribed average SPL level so I can't imagine how it could ever sound right. It would be like designing a speaker that could only play one song on a recording well, and that would only be at certain level.

Best Regards,
TerryO

[GDO]

Acording to the Fletcher/Munson curves we will percieve mid-range as louder compared to the bass given the same SPL.

Yes but those curves are embedded in the records by the guys who make the records because they make the records using ears that follow those curves, so ... don't worry about that!

[Robh3606]

I've been reading up on the general opinion concerning what SPL levels one should design for.

Well it depends on several things probably the most important is what are your anticipated listening levels going to be and what type of music do you listen too. If you want anything approaching realistic peak levels you may want to up your speaker efficiency above 90db.

The main issue is most speakers are on the wrong side of the power curve. You really want to start out with a system close to 100db @ 1 watt 1 meter. The 1 meter number is one thing but remember you need to design for your desired SPL at your listening position which is dependent on distance. It's very obvious when you work the numbers out that once you need over 100 watts to get to your SPL goal the power requirements simply get out of hand. 3db is 200 6db is 400 and 10db is 1Kwatt. You are much better off starting on the higher sensitivity side of the curve.

My average listening level is in the mid 80's but my speakers are set-up to reach over 115db peaks at my listening position. That's through their entire bandwidth from about 25Hz and up. It all depends on what you want.

Rob