Cone Excursion Exceeding

[Tarun Nigam]

Hi,


I have been designing.my 2 way bass reflex speakers and now they are complete, Proud moment for me , I have checked the frequency response which seems to be ok, however removing all these biases I like them when they play music.

I am stuck at one point here on my winISD model, where it shows me Cone Excursion exceeds limits from 59Hz to 145Hz over full signal power of my amplifier @40Watt. I am paranoid on this as I fear that may damage my Dayton speakers at this level. The cone excursion starts to exceed from 10watts of power.

I am attaching the graphs from winISD and need your inputs and opinion how to limit the excursion as I am stuck in the situation. Also I will appreciate any other design inputs good or bad on improving the design.

Thanks folks and look to have your support, help is welcome.!!!!!!



Regards

 

[fpitas]

You may not want to hear this, but...just don't turn the volume way up? Little bitty woofers can only do so much.

 

[fieldcar]

You may not want to hear this, but...just don't turn the volume way up? Little bitty woofers can only do so much.

Pesky physics strikes again.

I'd suggest a MiniDSP 2x4HD + Umik-1. You can set up dynamic range compression and EQ out low frequencies to your taste. Eventually, you can do it right, and get a nice subwoofer.

 

[raindance]

At full signal power your amp will clip and destroy the tweeters also. Just don't listen at full power.

 

[alex-z]

Use less power, and high-pass the speakers. Bring in a subwoofer with a low-pass filter. It is unrealistic for any speaker with a 5.25" woofer to be used without a sub.

Also, you should really flush mount your tweeters, and round your baffle edges. You can reduce diffraction substantially, giving you a far smoother frequency response.

 

[DVDdoug]

You probably won't damage the woofers but they might distort. And if they distort too much you'll probably turn it down.

 

[egellings]

Ya just can't send a 5.25" woofer out to do a man's job.

 

[fpitas]

You probably won't damage the woofers but they might distort. And if they distort too much you'll probably turn it down.

Yeah. Sensible people don't destroy speakers (usually), because they sound so awful when you stress them.

 

[AudiOhm]

What are your crossover frequencies?

How did you calculate the box volume, port width and length?

Did you add internal bracing and insulation?

Ohms

 

[Prana Ferox]

Those boxes look very pretty and also way oversized for that driver.

 

[30 Ounce]

That port looks huge for that driver. What is the tuning frequency? Looks like a good choice for a tennis ball.

 

[audiofooled]

Hi,


I have been designing.my 2 way bass reflex speakers and now they are complete, Proud moment for me , I have checked the frequency response which seems to be ok, however removing all these biases I like them when they play music.

I am stuck at one point here on my winISD model, where it shows me Cone Excursion exceeds limits from 59Hz to 145Hz over full signal power of my amplifier @40Watt. I am paranoid on this as I fear that may damage my Dayton speakers at this level. The cone excursion starts to exceed from 10watts of power.

I am attaching the graphs from winISD and need your inputs and opinion how to limit the excursion as I am stuck in the situation. Also I will appreciate any other design inputs good or bad on improving the design.

View attachment 264781

Thanks folks and look to have your support, help is welcome.!!!!!!



Regards

I'm glad that you're happy with the way they sound and you should be proud, DIY is not an easy task. As others have said, don't push them to hard, for sure you will hear when they start to get to their limit.
In your case, WinISD predicts around 7 watts should be enough for them to reach xmax, and by then, if you take a look at the SPL plot, they should be putting out 96 db and be ok with excursion until 45 Hz or so. Indeed, WinISD design is within Dayton's TS parameters. They do say their power handling is 40 watts and they say nothing more but this doesn't apply to a full range of frequencies. At 40 watts, its 104 db SPL and this is physically impossible for these tiny drivers. So listen, enjoy, and don't worry about it. In reality, with a pair of these and some room gain they should get plenty loud and don't require a lot of power.

 

[fineMen]

... where it shows me Cone Excursion exceeds limits from 59Hz to 145Hz over full signal power of my amplifier @40Watt. I am paranoid on this as I fear that may damage my Dayton speakers at this level. The cone excursion starts to exceed from 10watts of power.

Easy, won't happen when listening to music, hopefully. I didn't check the attachments, because the phenomenon is regular.

First the music won't consist of just bass. The mids need at least the same amount of power. The part which could overload the bass reduces to 20W. That's just double of what the woofer could take in its 'linear' regime. Double of power translates to 1,4 times the excursion. An overexcursion by that little won't destroy the driver.

Second, as already stated the driver is going to sound awfull at its max excursion. That should be acknowledged as the signal to stop cranking it up. A high level of blood alcohol is more dangerous than a big amp in itself.

Congrats!

 

[fpitas]

A high level of blood alcohol is more dangerous than a big amp in itself.

Words to live by.

 

[Tarun Nigam]

Pesky physics strikes again.

I'd suggest a MiniDSP 2x4HD + Umik-1. You can set up dynamic range compression and EQ out low frequencies to your taste. Eventually, you can do it right, and get a nice subwoofer.

Thanks for the idea, I suppose I can go for High pass filter but that will reduce the low frequencies.

 

[Tarun Nigam]

Use less power, and high-pass the speakers. Bring in a subwoofer with a low-pass filter. It is unrealistic for any speaker with a 5.25" woofer to be used without a sub.

Also, you should really flush mount your tweeters, and round your baffle edges. You can reduce diffraction substantially, giving you a far smoother frequency response.

Thanks alex for response ,I suppose I will try pairing them with Subs. The tweeters are flush mounted and press fit , but yes baffle edge needs to be rounded.

 

[Tarun Nigam]

Easy, won't happen when listening to music, hopefully. I didn't check the attachments, because the phenomenon is regular.

First the music won't consist of just bass. The mids need at least the same amount of power. The part which could overload the bass reduces to 20W. That's just double of what the woofer could take in its 'linear' regime. Double of power translates to 1,4 times the excursion. An overexcursion by that little won't destroy the driver.

Second, as already stated the driver is going to sound awfull at its max excursion. That should be acknowledged as the signal to stop cranking it up. A high level of blood alcohol is more dangerous than a big amp in itself.

Congrats!,

Thanks for appreciating FineMen, Can you please elaborate more on how bass will reduce to 20W, I cannot see this from the graphs anywhere. The woofer are 40W RMS.

 

[Tarun Nigam]

I'm glad that you're happy with the way they sound and you should be proud, DIY is not an easy task. As others have said, don't push them to hard, for sure you will hear when they start to get to their limit.
In your case, WinISD predicts around 7 watts should be enough for them to reach xmax, and by then, if you take a look at the SPL plot, they should be putting out 96 db and be ok with excursion until 45 Hz or so. Indeed, WinISD design is within Dayton's TS parameters. They do say their power handling is 40 watts and they say nothing more but this doesn't apply to a full range of frequencies. At 40 watts, its 104 db SPL and this is physically impossible for these tiny drivers. So listen, enjoy, and don't worry about it. In reality, with a pair of these and some room gain they should get plenty loud and don't require a lot of power.

Thanks for the response and giving me confidence.

 

[fieldcar]

Thanks for the idea, I suppose I can go for High pass filter but that will reduce the low frequencies.

This is why I'd play around with a low shelf filter and/or a limiter rather than just kill off low frequencies altogether with a HPF. If you get a subwoofer, then using a HPF is a better idea.

 

[Tarun Nigam]

Those boxes look very pretty and also way oversized for that driver.

Can you suggest optimum volume and tuning freq where the cone excursions are within the limits.