Appreciate you watching too!

Yeah, and that kind of technology is getting popular again.

Thanks Randy! good to see you still online too.

Yes! I actually have a video planned on talking about full bridge vs. half and the power usage. One thing to keep in mind, amps typically have better efficiency at higher ohm loads. So, a 10k half bridge amp at 1 ohm maybe 70% efficient. However, it could be 85% efficient at 4 ohms. You may just want a bigger amp and wire up some to be more efficient. Those full bridge amps can be very efficient as well.

Based on air density as the denser the air the higher rise you can see. This varies some with back pressure and port area as well. Omg now you’re talking about box tune.. that’s what I’m talking about.. people think rise is a product of the voice coils heating up under power.. it’s a fraction of a percent really. .rise is a product of air pressure on the cone creating air resistance back against the driver. The reason you should have no rise at tune is because front and back pressure is equal and the cone isn’t moving. The more movement (xmax) the more rise you will see. Other characteristics that matter is soft or stiff suspension.. you get almost no rise from a sealed box of proper volume. The reason is the driver is sucking the vacuum inside the box while trying to push the air outside endless spring and is assisted and resisted in opposition and balanced out. It’s also a calculation of cone area to xmax in relation to air density.. meaning all things equal.. a 8” will have a lot more rise then a 15” Subs designed for small boxes like DC will on average have less rise in application when having same power and xmax. You mention the evl here.. evls on average so like slightly smaller boxes then similar subs in that range. Take a sub not installed.. hook your meter to it.. leave meter hooked up now push down on the cone.. now push up on the back of the cone.. notice the impedance changes? It has almost 0 to do with amplification

@@fishrrelaxing9361 You totally get it! These are the things I have been testing for the last few years! Brilliant deduction! I am just trying to share these things in bite size bits so my videos can be somewhat short. There is so much to speakers, subs, car audio, etc. It takes a lot of videos to cover simple topics and I still have to choose what to leave out to make them simple!

@@fishrrelaxing9361 By the way, I am so glad that you mentioned that smaller diameter subs will have greater rise! I literally asked that question in a group one time and had people think I was crazy. The group felt that I didn't understand how rise worked! Eventually, I figured it out when i tested Sundown U 18's vs 10's, same motor structure, box based on manufacturer specs. Then a little bit of research, and I finally figured out that rise has a lot to do with cone size!

@@caraudiolab I think you miss took my comment on size.. But as for testing.. I’ll save you a lot of time on rise.. rise has a lot to do with port sizing on reflex boxes as well as box sizing.. say mfg x recommends box size of .75 You know after charting that sub you can get a flatter and higher spl response by going to a 1.25 box and maybe tuning it at 36 instead of 33 per say. Now the larger box means the driver is more efficient.. so less power needed and likely won’t do rated power anymore.. with that comes port area.. maybe at .75 you could get away with say 12sq in the port.. but at 1.25 that same build will need now 14.5 sq.. this will also very based on vehicle and loading distances but getting back to rise.. you may see 1 ohm rise at .75 and .75 12sq cause you have a lot of back pressure in the box stiffening the sub.. 1.25 and 14.5 sq you’ll see say 3 ohm rise (we assuming say running at 1ohm here in this) Now you double the subs and all this also double which is why a lot of people see rise to 7-8ohm a lot of the time.. Now say all this was true for x sub in y box at say 70* f. Now drop the temp to 55* and now the rise is only 1.5ohm. Air density got thicker cause of lower temperature and as such added more back pressure to the sub.. If you really want to mess around with rise issues. Throw out that software.. take temperature readings of the air inside the box.. keep the sub and amp the same. Don’t even adjust he gain or anything.. use a meter to monitor the output not the volume knob at the source.. do a small sealed box. Large seal box.. Do a small reflex and medium reflex.. I’d say throw in a 5th order box as well.. Then do a horn.. Measure db output, current draw, actual real work output power and the air temps.. When you do all this you’ll understand a lot about why certain applications perform or don’t for intended or non intended use.. What you’ll come to at the end of all this research.. is that box rise actually doesn’t mean anything at all! It’s all a product of design.. we already know when overdosing a box it will take less power.. the sub does this for you with impedance rise lol.. We already know a small undersized box will soak up power.. the sub does this on its own by no or little impedance rise.. The magical world or when mechanical engineering meets acoustical engineering meets electrical engineering.. it all balances itself out and rise is already factors into the equation in the electrical side of things because of how the mechanicals and acoustical sides work. Now the one place you can play around with this. Running at higher ohms in the first place.. if you’re wired down to 1 and see a rise to 7.5.. that same power bios etc at 2oh load may only rise to 3.5.. You’re not gonna figure this out with box building software.. its literally a collection of 3 different phd degrees to even began to get into this.. all you need to know is that the issue is actually steady accounted for by total system design as a whole.. air temp is actually more influential from an outside world perspective to this then anything we can actually control ourselves by design..

And the reason why you have rise the further and more the cone moves, is because its a coil inside a magnet, its an electrical motor. Just like any other electric motor, you can use it as a generator. As it goes back and forth, it creates emf power back to the amp, which the amp has to overcome.

You really have to know what you are doing to get a good bandwidth with a 4th order bandpass, but it is totally possible. If you are talking about a 4th order regular ported box, yes you can get that type of bandwidth. You would probably have to go on the larger recommended box size .35 cubic feet and the lower recommended tuning of 35 hertz (maybe even 34 hertz). But, you would have to watch your power, too much could damage them with a bigger box and lower tuning. I had my U10's tuned at 35 hertz and I played really well from 30 to 70 hertz.

A series 6th order double bandpass will give you the best bandwidth and some control over your subs at low end. However, that will probably be to big overall.

@@caraudiolab thank you for the detail reply...its much appreciated....I too was considering a 6th order or even a 3 chamber bandpass buts is my first time building a box...its scary to attempt complex boxes with limited experience

@@Kevin-21 Completely agree, I have built some boxes that didn't work out in the past myself, I learned a lot through the experiences.

Sure, I added it to the video description.

@@caraudiolab Awesome, thanks