So I’ve been trying to work on my kinda stupid idea. Found I can’t seem to make the dual 7" drivers really work. Either there’s air velocity over 17, or excursion is too high, or I can’t get it tuned below 30hz (I get stuck around 31-32hz, and can achieve the same with dual 5.25)
The tuning frequency of the port does not directly correlate to the Speaker tuning. If you tune to 25hz you get a slightly dropping of response but your F3 is at 25hz (coincidence lol)
If you have too much air velocity increase the vent cross section. it will get unreasonably long fast so beware
speaking from personal experience you can safely go over the 20m/s “rule”. for the 25hz BR tuning frequency a 8cm x 34cm tube will net 30m/s at 100W. Thats 106dB on average. Thats stupid loud. So dont restrict yourself too much there. A flared port also reduces possible chuffing.
IMO use WinISD for the Bass tuning and tools like VituixCAD for the actual crossover and speaker matching. Its way stronger and easier to work with. But thats personal preference.
Lastly the tweeter choice should be fairly unproblematic. From the datasheet a 2500hz Cutoff with a 2nd Order Filter should be doable. Then Choose a tweeter that works fine for that and is good in itself
VituixCad has the SPL Trace tool. You can just screenshot the datasheets graph, load it, and the klick on trace spl or Z and then klick on the line from left to right. Thats how I did it. You also need to drag the Bars to the upper and lower limits for it to know the scaling.
And isnt the 7" one the E180HE? Anyways do I understand it correctly that you want to use 2 E150 for the Bass and another E150 for the mids? Id recommend going with a slightly bigger box and Dual E180 for the bass and then an actual midrange driver for the mids. The Epiques are really interesting bass drivers but id assume you get better distortion and dispersion with an shallower mid driver.
A box of 10x13x25 with it tuned to 28hz would seem like a good way to do it.
I originally wanted to use the 7", though I couldn’t seem to get things to work right without too much excursion, the port being too long, or too much air velocity (at least when trying to target 17 or less).
I’ve toyed with the idea of using a different mid-range driver, though finding one that is be confident in has, admittedly, been a challenge.
Edit: there are a few that may have caught my eye… One may have a visual appeal factor, another may have a more technical factor.
Relatively inexpensive, decent reviews, no branding on the face, high sensitivity…
Decent frequency response, phase plug(I might be a sucker), high sensitivity
Biggest downside is the big branding on the dust cap
Simply speaking of the Physics a larger diaphragm will always have to move less to produce the same pressure differential aka SPL compared to a smaller diaphragm. This is also the case with the Epique boys. Given the same SPL output the 180s move 12mm and the 150s move 15mm. That is with both in a similar tuning with an F3 roundabout 28hz. I found a 7cm diameter tube to be “fine” in regards to the air velocity but i wont force you to follow my view on the “limit” so decide for yourself. A note on that since the port gets shorter for the same tuning with a larger box its usually easier to get a nice reflex tuning with large speakers while Bluetooth speakers tend to go with a passive radiatior.
Regarding the Midrangers you mentioned I have never heard of either of those which means exaclty nothing so do as you will. I can however give you some tips and my personal experiences.
Try to look for independent measurements of axial, off axis and distiortion measurements. It will usually make things a lot easier in the end. Generally People like Erin from ErinsAudioCorner and Hificompass are great guidance imo.
Generally i’d look for a even and gentle falloff into the higher regions. That makes mating to a tweeter easier. Also Distiortion should be under 1% for most of the necessary regions. And the flatter the region you want to use is the easier your Crossover will get.
I personally have used the SB17CAC for a 2 way and from Erins review you can see its really smooth up to about 1.5kHz where things start to get “interesting” so thats where i start to cutoff and the rest was a breeze. For your uses the beaming or falloff off axis is a bit early with this one so you might consider the 4" version in the next link. It should be fine to about 2.5 or 3k
What I also used was a fullrange driver from TangBand, the W4-1337SDF (I also couldnt resist the “nipple” charm lol). It works really nicely as my dedicated midrange from 200Hz to about 3.5kHz. Distortion is good yet not quite as nice as the SB but is easier to integrate due to its nicer falloff. TangBand W4-1337SD | HiFiCompass (the sd is the neo version which doesnt differ that much otherwise)
Lastly I saw the Wavecor WF120BD03 other there. I have not used it myself but it shows a wonderfull FR and Falloff with Pretty good distiortion. Generally I’d assume it to handle nicely
Also as much as I am talking about the measurements here each enclosure will shape the drivers further. So its always necessary to measure it after assembly and THEN design the crossover for it. But the better behaved a chassis is in the first place the more likely it will behave nice once installed.
All that said you should choose for yourself what you think makes sense and what you want to target in the build. And what i listed is just what i happened to use and what looks good on a monday at 4am
Given that I’ll be using Starkrimson Ultra modules to power each section, each with their on power supply and the rail capacity upgrade boards, and being fed by a miniDSP Flex (amp modules and miniDSP linked below), I’ll be using the miniDSP to act as an active crossover for the bass region and the link between the bass and the mid-range. I will then have a passive crossover in the speaker handling the midrange and tweeter. I have considered using the non-ultra amp modules for the mid-range/tweeter portion
I’m now a bit confused as to exactly how to calculate the load on the tweeter and midrange drivers, given (I’m presuming here) that they will be wired directly to the crossover. I’m guessing it would count as parallel. Is this correct?
Edit: I get I am going for a very ambitious project that is going to hurt my bank account allot.