alpair 7 excursion in winisd

[doors666]

Hi,

I am planning to make a desktop speaker build from these. Since space is less, I was considering 6.7 ltrs sealed box or the smallest ported box possible at around 11.2 litres, tuned at 48hz. I tried to simulate these in winisd and saw that the excursion exceeds max limits at around 90hz. To bring the excursion below limits, the power needs to be brought down to around 10w. the ported box showed this even if I increased the volume to 200ltrs. Am I doing something wrong here. Do I need to put an hpf in this? It should not be the case that I play the first song slightly loud and it blows. How are people handling this issue in general.

I am attaching the winisd driver file and image for this.

 

[Scottmoose]

No, you're not doing anything wrong. But what else did you expect? We're talking a small, low - modest efficiency FR driver here, not a 15in woofer. It's always going to be moving a fair way to generate low bass and / or higher SPLs unless you horn load it. It won't blow unless you have no mechanical sympathy at all, but common sense is also required regarding practical limitations. If you need high SPLs & low bass, you either need a bigger driver, dedicated LF units in support, or horn loading.

 

[planet10]

The largest vented box i was happy with was 9 litre. 5-6.5 litre sealed.

dave

 

[doors666]

No, you're not doing anything wrong. But what else did you expect? We're talking a small, low - modest efficiency FR driver here, not a 15in woofer. It's always going to be moving a fair way to generate low bass and / or higher SPLs unless you horn load it. It won't blow unless you have no mechanical sympathy at all, but common sense is also required regarding practical limitations. If you need high SPLs & low bass, you either need a bigger driver, dedicated LF units in support, or horn loading.

Well, my only diy experience is making a 15" sub so far, so I guess you know where I am coming from🙂. I expected the output to drop significantly as its a small driver, what I did not expect is that it will exceed xmax in its stipulated power ratings in a sealed box. Anyway, good thing is that now I know the limitation, I can use it more wisely🙂. I went for this driver due to its sound quality, not spl, I guess I was a bit surprised by the winisd plots.

The largest vented box i was happy with was 9 litre. 5-6.5 litre sealed.

dave

I am leaning towards a sealed one with Height – 10”, width – 7”, depth – 9”. Gives me about 6.3 liters internal with 15mm wood. Does that sound good. I plan to use no bracing (atmost baton bracing), do I need to go for thicker wood? What about the placement of driver on the baffle, is placing the driver bang in the middle fine. Do you by any chance remember what dimensions you used for the sealed one. Any recommendations on lining, filling etc.

I will be using a sub also, this is for desktop use.

Dave, I remember you mentioning that you have jack hidley's plate amps. Do you know if the speaker level output from the plate amp is highpassed or does it send the full output to the speakers, the documentation on the site doesnt mention it.

Thank you for all the help guys...

 

[planet10]

I am leaning towards a sealed one with Height – 10”, width – 7”, depth – 9”. Gives me about 6.3 liters internal with 15mm wood. Does that sound good. I plan to use no bracing (atmost baton bracing), do I need to go for thicker wood?

.
That should work. 15mm + bracing will work better than 18mm... i always feel you get the best downward dynamic range if the driver is coupled to at least the back of the box. We have 2 braces in our (nominal) 5.5 litre BB miliSize boxes

Dave, I remember you mentioning that you have jack hidley's plate amps. Do you know if the speaker level output from the plate amp is highpassed or does it send the full output to the speakers, the documentation on the site doesnt mention it.

I don't have one on hand but the schema shows no outputs except to the woofer.

dave