19 vs 22 vs 25mm tweeters and power handling

[alecf]

I've seen it said that larger dome tweeters "can take more power" than smaller domes. Is this indicated in the tweeter datasheet or is it more a generalization?

Assume I have a 100w solid state amp in a small/medium room and like listening at moderate-high volumes; would there be different limits on how loud I could play (for example) a Vifa D19 or Hiquphon OW1, vs say a Vifa DX25 or D27 or an SB29?

Is it simply a function of the size of the tweeter? Does dispersion also play a role in this? Thanks.

[Ugg10]

A couple of initial comments, if you are using a passive crossover then the 100w is shared by all drivers with the tweeter typically getting about 5-10% of the full power also there are some small tweeters around that have reasonable power handling, the Wavercor TW022 for example is rated at 70w long term. The final thing is that “moderately loud” in most cases is probably about 80-85dB continuous with 100-105dB peaks (note at 85dB continuous in the work place you need to provide hearing protection) so most of the time your 92dB/W/m will only be being fed a couple of Watts continuous with occasional peaks of 20-30dB.

Just a few thought, however if you plan on feeding just the tweeter 100w then your continuous volume would be in the 105-110dB range which is in the Pain region.

[LOUT]

I think the size can be a mediocre rough indication of how loud it'll get which is determined by BOTH watt-handling and efficiency (how loud it gets watt-per-watt). You don't usually see super loud 1/2" tweeters, but I feel like there are plenty of dome tweeters ranging from 22-25mm that top out around the same volume.

The size can also sometimes be a good starting point for how low you can get away with crossing it (larger surface-area means less movement is needed to reach the same loudness even at slightly lower frequencies), so you'll generally end up looking at 25mm when you need to cross a little lower (horn-loading the tweeter properly can also help even more for this).
That said, tweeters that are better at reaching slightly lower frequencies are often balanced out by having lower efficiency (less loudness watt-per-watt).

Pretty much the only guaranteed thing you'll change with size is how wide/narrow the dispersion is at the highest frequencies...but I don't think there's a huge difference between 19-25mm there (there's certainly a difference, but I don't think I'd recommend limiting your options one way or another over the amount there).


I think you'll typically find most decent dome-tweeters are capable of outputting 100-105db, so loudness isn't usually the problem unless you're filling a really large area.
That's loud enough to damage your hearing in 15minutes or less...so I'd call it plenty loud.


Unless you're trying to cross the tweeter too low, you'll practically always end up limited by the woofer before the tweeter has neared its limit. And the woofer will often be limited by its XMAX before it's limited by its watt-handling (XMAX is how far it can move forward/backward before distortion increases drastically, and deeper bass requires a lot more movement than mids or highs of the same loudness)

[rpb]

I've seen it said that larger dome tweeters "can take more power" than smaller domes. Is this indicated in the tweeter datasheet or is it more a generalization?

Assume I have a 100w solid state amp in a small/medium room and like listening at moderate-high volumes; would there be different limits on how loud I could play (for example) a Vifa D19 or Hiquphon OW1, vs say a Vifa DX25 or D27 or an SB29?

Is it simply a function of the size of the tweeter? Does dispersion also play a role in this? Thanks.

Some tweeters dissipate heat better due to the materials they are made out of. Two tweeters might play equally loud without breaking, but one may sound better than the other at reasonable / spirited spl levels.

If you cross at 3k, you can likely play louder than if you cross at 2k..

[alecf]

Thanks I think my takeaway is that tweeter diameter does not necessarily correlate to power handling, whereas dispersion is better off axis with smaller domes.

If that's the case, why are 1" domes so predominant in, say, commercial speakers when a smaller dome would have better off axis response and allow a little better closer spacing to a midwoofer?

[rpb]

Thanks I think my takeaway is that tweeter diameter does not necessarily correlate to power handling, whereas dispersion is better off axis with smaller domes.

If that's the case, why are 1" domes so predominant in, say, commercial speakers when a smaller dome would have better off axis response and allow a little better closer spacing to a midwoofer?

Strong off axis response is not necessarily a good thing. I think that close driver spacing is somewhat over rated.

[Chris Roemer]

Oh (to your initial ?), I'd say that in "general", a 1-1/8" dome will take more power than a 3/4" dome, simply because the dome size is very close to the voice-coil size. An 8" driver can take more power than a 4" (larger v.c.), and (typically) a 12" can take even more. The larger v.c. also can dissipate more heat.

[LOUT]

Thanks I think my takeaway is that tweeter diameter does not necessarily correlate to power handling, whereas dispersion is better off axis with smaller domes.

If that's the case, why are 1" domes so predominant in, say, commercial speakers when a smaller dome would have better off axis response and allow a little better closer spacing to a midwoofer?

The dispersion and center-to-center distance differences are probably nothing too huge, and I'd guess the pricing/shipping/availability of parts plays a major role.
Some tweeters might also happen to work noticeably better than others when using a really simple XO like a single capacitor and resistor (or they might simply be more robust for handling a shallow rolloff from a simple capacitor and resistor XO) which saves money for both copper/inductor cost and for labor costs via less complexity of assembling the XO.
There's a lot of stuff that matters a lot more or a lot less to a DIY build compared to a large scale (or even small scale) manufactured speaker....at least that's my assumption.

[dynamo]

Power handling of any dynamic driver needs to be looked at from two angles, thermal and mechanical. For instance the power handling spec on a woofer is rarely a consideration for most home audio speakers because they are typically loaded in a way that they will reach mechanical limits (xmax) long before their 100w or whatever thermal rating.

A driver with a larger surface area (be it a woofer, mid, or tweeter) will move more air with the same amount of excursion than a driver with a smaller surface area. So a smaller driver will likely reach mechanical limits sooner when outputting a sound than a larger driver playing the same level.

Also the crossover topology can play a huge role in the tweeters ability to live and stay out of distortion with higher input levels regardless of its size. Steeper slopes and/or higher crossover frequencies in high power applications can make a big difference.

So an answer to can bigger take more power - in theory yes, but not always, many variables.

[billfitzmaurice]

why are 1" domes so predominant in, say, commercial speakers when a smaller dome would have better off axis response and allow a little better closer spacing to a midwoofer?

Because the smaller the dome the higher it usually must be crossed over. If you've got a 1/2" dome that must cross over at 4kHz or higher then the midbasses must have adequate response and dispersion to reach 4kHz or higher.

[wogg]

Design and material differences aside, there are a couple physics properties that are directly related to the diameter of the speaker.

Dispersion is a property of the wavelength vs. the radiating diameter. As frequency goes up, wavelength goes down and dispersion is wider. Or if diameter goes down, dispersion is wider at the same frequency. This relates to power response in the room and has lots of discussion about that. Generally, off axis response should be smooth and show a general drop in response at high frequencies as you move off axis.

Maximum SPL is a function of frequency, driver diameter, and Xmax. The smaller the diameter, the higher Xmax is needed for a given frequency to hit a certain SPL. Of course with all speakers, higher excursion means higher distortion (generally, design can affect how bad). So the smaller the tweeter, the lower the SPL limit at lower frequencies which is generally compensated by raising the crossover frequency.

As with everything, choose your tradeoff.