An earlier post here says you are correct, the heading states: "Additions and Changes Make These Speakers Sound Its Best". They meant to say "Here are possible changes you can make.."
NOTE: in terms of improving the bass. The Skunkie Design YouTube channel built both the 2.2a and 3.1 and felt the 2.2a had far better bass.
She changed the woofer in her 3.1 to another HiVi woofer and says it is now much improved. This is the
woofer she used. It appears to be almost identical to the woofer in the 2.2a, except with a different cone material. Note, Stephe is not a speaker expert and just did a straight swap. It sounded better to her, and it does fit.
I recommend thinking about the following before you buy the yellow cone drivers.
I'm an expert now - no not that just kidding, that said maybe I can save someone $150.
So unless you just want some yellow cones that
are not an exact fit(electrically) or maybe not even a decent fit for the crossover, (and you want to buy them based on purely the subjective opinion of someone who doesn't exactly come across like the next Andrew Jones in the video) maybe skip them.
Pulling parts, replacing and praying is a part of DIY fun but I think we could go at least a bit deeper here.
The Hivi L6-4R included with the kit is 4ohms
The Hivi yellow cone D6G you linked is 8ohms
Plus they are different in other parameters, including the effective sensitivity of the L6-4R is much higher than the two D series drivers(yellow cone and 2.2a).
I have measured the 4ohm L6-4R as 91.49db SPL w/2.83v
I have measured the 8ohm D6.8 IIb as 85.66db SPl w/2.83v
Pretty big sensitivity difference here even if you decide to calculate @ 1watt.
This means the crossover in the midrange is likley going to be off by an objectively significant amount due to both sensitivity and impedance differences, not to mention any frequency responce deviations. I mean we are buying these because they measure really well. This potential change should be meaured by that video host.
The ASR measurements here for the 3.1a are excellent.
The bass goes deep enough for a 6.5" with a smooth roll off, and without overly threatening the driver's x-max.
That should allow great in room extension to 35-55hrz depending on the size of the room. You will have your room modes and SBIR(peaking and nulls due to the rooms size and shape and placement) to deal with but that will always be the case.
If you need better bass, buy/make subs. If subs are a non-starter and you do not listen loudly, use tone control or EQ/PEQ to turn up the bass a bit.
If you listen loudly and especially if the room is on the large size you will need subs or towers. A pair of 6.5" drivers simply can not handle high or even medium high SPL @ 40-45hrz unless the room is tiny or they have a true 10-12mm xmax.
I don't know what frequency the 2.2a enclosure is tuned to, the 3.1a is tuned around 48hrz. It is possible the 2.2a is tuned slightly lower or that it has a tuned bump. In any case tuning a 6.5" on the low side works for a lower output system but will stress the woofer at higher output and could damage it in some cases.
I don't know why the 2.2a was perceived as having 'better' bass, nor why a mismatched woofer (the yellow one) would be so great. The host could show some basic measurements and explain why. It could just be bloated or poorly tuned extra bass that someone perceives as great. It could also be truly 'better' or perhaps as mentioned tuned lower. It could also be subjective biases.
Ultimately HiVi does charge more for the D series (the yellow cone and the black one used in the 2.2a speaker) vs the L series woofer used in the 3.1a. That may make it appear like an upgrade however a speaker is a system and needs to be taken as such.
The D6.8 IIb in the 2.2a and the yellow D6G are very similar drivers, the main difference is the cone material, not much else. The woofer used in the 3.1a is more modest price wise but is a simpler design and that is cheaper to make but not nessicarly of less ultimate quality.
Like most 6.5" woofers made, none of the 6-6.5 '' Hivi woofers have the specs for being bass monsters in any sort of high SPL system. Pair them with an electronic high pass and supplement with subs for that expereince.
as an aside there is now a real mark II version of D series woofers out on the market, they look pretty cool tech wise. I wouldn't use one here but in some other project they might be Dynaudio clone fun.
