@djn I remembered a informative discussion about aperiodic ‘holes’ etc…… that may be of assistance. 😎
https://www.diyaudio.com/community/threads/when-is-a-port-not-a-port.337840/#post-5788870
https://www.diyaudio.com/community/threads/when-is-a-port-not-a-port.337840/#post-5788870
Here is the WinISD results in a vented box with a 4" port that is .75" deep. It looks like a good starting point and I will turn the port into an aperiodic port and measure the results before and after.
Agreed, but I can reduce the internal volume with bricks, make the vent like an aperiodic port, seal it, for example. I already have one 3 cu ft cab, so this is all just a test.
So, it in the 100s in the last weeks and for the next couple weeks. Obviously I’m not spending time in the garage. But I have been thinking about the project.
When I look at the curve, I was thinking about for most people hear very little change in volume when dropped or raised 3db.
The high and low in the graph is 5 difference. So will I really hear that difference when actually playing music?
When I look at the curve, I was thinking about for most people hear very little change in volume when dropped or raised 3db.
The high and low in the graph is 5 difference. So will I really hear that difference when actually playing music?
I went out to the shop today at 6am to straighten up and prep for this built. It was 72 degrees. I have the MDF and found a 3-way active crossover I thought I gave to my brother. So, I’ll assemble the cabs tomorrow morning before the heat hits.
Could be worse temperature wise. We've been over 115 F this last week. Can't wait for it to cool down again.
It's still too hot to work in the garage. but I've been messing around with WinISD and just by changing the tuning frequency I got the line a little straighter. I will tune it when I build the first one, but I've got nothing better to do right now. The cab is 3 cu ft with a tuning freq of 33hz.
That sim breaks my first rule of vented boxes. The first derivative of the FR curve shouls only pass thru zero once.
dave
dave
It will be interesting to see how changing cab volumes and messing with the vent in terms of length and/or stuffing it with mesh.
Geez, I guess I’m a true Northern boy at heart. This is the norm snowfall growing up. I went out to the shop today to work on the cabs and it was still over 100 outside. I’ll have to wait for the fall.
Finally cool enough to work in the garage. Here is a question: if WinISD says I need a 4” x 1” port in a cabinet and the cabinet is 40” tall, what would happen if I made 5” holes in each of the internal baffles used to stiffen the cabinet with the final port vent near the bottom 4” x 1”
In other words mess with the hole size inside the cabinet.
In other words mess with the hole size inside the cabinet.
I have the MDF all cut and ready to assemble in a couple weeks. I plan on using a 3-way active crossover and three amps. When I get it all dialed in, can I assume I can build a first order crossover to the frequencies points I set with the active crossover?
I use them in my main system and, to my ear, they sound thin in the vocal region of the midrange. I use a wood horn and CD in that region and like it much better.
Ok, I was using them on a horn (and plan to build some more), so they did not seem thin to me. But still, the Heils are the best tweeters to my ear.