Upgrade speaker, advice?

[funkydoug]

Hi Stevie, patience was in short supply this morning

 To be honest, I enjoyed it and was thankful that the results were pretty positive, fortunately! 

I will A/B compare the ports for sure. 

There's no room for a 100mm port, I considered that. I don't think I'll be doing amymore sawing, so it'll either have one 75mm port, or I'll keep them both. 

How do you model a cab with 2 ports of different sizes? I've got WINISD but cant seem to do that. 

Finally, the 37 litres turned out to be an overestimation. More accurately measured it is 34.1 litres. 

 

Thanks again guys, and don't worry, if I end up making a huge mess out of it I will only thank you for your input and inspiration Anything that goes wrong is entirely down to my trigger happy approach! 

[stevie]

Sounds good. Shame you can't fit a 100mm port in there, but you should find the 75mm one an improvement on what you have. I wouldn't recommend you keep the small port, but you can always experiment and it's your choice.

To get the tuning frequency for the port arrangement you have now, I split the difference between your original port tuning and what a 75mm hole would give you. I wouldn't bet my life on it though.

[Phil Starr]

Win ISD will cope with two ports but assumes they are both the same length and size. I wouldn't want to have to do the calculations for two ports so completely different. Conventionally you'd treat two ports (or any number of ports) as if they were a single port with the same area as all of them combined. with a 55mm and 75mm port that equates to a 93mm port. Remember the volume of the cabinet is decreased by the ports and the volume of the speaker itself so this is probably a 30l cab in reality.

The 75mm port is nearly twice the area of the 55mm port 44cm²    plays 24cm² so you should have a noticeable improvement with just that change.

[itu]

Good answers from Stevie and Phil Starr.

A basic triangle to consider when thinking of speakers and cabinets is:

Volume - Lowest frequency - Efficiency

If you make the cabinet bigger, it can have better efficiency or it just goes lower. If you want to keep the volume as is, you may affect the lowest frequency if you want better efficiency.

This is pretty much the same as with cameras, where you have ISO - Speed - Aperture. Alter one, and at least one of those two others is altered, too.

[funkydoug]

The second port arrived and fit the hole effortlessly. I plugged in with both port tubes in place and it sounds great, certainly seems a lot less constrained in the bass range and not at all boomy, just a better, bigger sound. 

In looks tidy and as the baffle is made of thick MDF and is pretty small (as the cab itself is so small) I'm hoping it won't suffer in terms of stiffness / strength. It certainly seems solid. 

Very happy with it and as a result really don't feel the need to upgrade the speaker. 

Could be all in my head of course, but a placebo effect is still an effect! 

 

Pics for anyone interested :

Edited December 1, 2018 by funkydoug