The appearance of 2.5- and 3-way speakers look similar, actually identical for some designs. Suppose they both have 3 drivers per cabinet for the same; a tweeter, a midrange, and a woofer. The difference that I could realize is the presence of the “high-pass filter” for the midrange. That means the 2.5 ways will allow its midrange to simultaneously play woofer’s frequency. By the way, I couldn’t think of the benefits of the 2.5 ways except for economic purpose. Furthermore, it may yield inferior quality to the 3 ways as the midrange driver will play mid-frequency based on low-frequency waves. I’m not sure if it could be viewed as the midrange in the leaked box, couldn’t it? So anyone please tell me what’s the benefit of 2.5 ways speakers over 3 ways?
Last edited:
Simplicity and lower cost mainly I gather. A well done .5 woofer takes away a lot of the bass from the main driver, adds boost to the bass octaves. My experience is positive even if it means having to use a cored coil with large diametre wire to keep the resistance losses as low as possible. Often not at the -3dB or -6dB baffle step frequency but dependent on what value coil I might have on the shelf. I often use a much bigger driver for the .5 woofer, say a 6" with a 4" + tweeter or even an 8". Current project has a 12" as the .5 but in a separate box
Now we should put in some numbers.
If I say 15 cm as the diameter of the woofer, and the dimension of the enclosure to be tall and slim, it follows that the doubling of the mid-woofers Is good...I guess... I've never heard nor stood in front of a pair...I mean: I've no friends, the only audiophile in town, few visits but noone has a stereo, go figure a WWT tower.
If I say 15 cm as the diameter of the woofer, and the dimension of the enclosure to be tall and slim, it follows that the doubling of the mid-woofers Is good...I guess... I've never heard nor stood in front of a pair...I mean: I've no friends, the only audiophile in town, few visits but noone has a stereo, go figure a WWT tower.
So I don't know what a 2.5 way might look now...if the 0.5 way is what you call the bottom, is the same 1 way that is assigned to the woofer, so it's a 3 way.
Minus 0.5.
I thought a 2.5 way only cuts off the midrange to one of the two bass drivers not bass to them.Typically the bottom woofer reproducing just bass and the upper one bass and midrange.At least that is the most common format.If the upper driver is just doing midrange then it is a three way.
It's the crossover that makes the speaker what it is, not necessarily the drivers combination, so yes just a coil on the .5 woofer but it still reduces the bass to the other driver so less Doppler distortion better power handling etc etc
First driver in the 2-Way sees all the program material that isn't treble, and if a 2.5 the .5 only sees bass
First driver in the 2-Way sees all the program material that isn't treble, and if a 2.5 the .5 only sees bass
I thought the requisite for 2.5 way speaker is to have two look- like mid-woofers. One could cheat by differentiating the parameters of the two like long-stroke in the bottom and more mid-refined...I mean, SS and SBacoustics have their dedicated M (midrange) series in the 12 and 15 flavor
Granted that if you use a larger driver it might go lower but I think the important part is the single inductor cutting off the highs at 6dB per octave. The XO works the same no matter what size the .5 woofer is; or my understanding is skew-whiffed and I've been doing it wrong for twenty years
I have owned some decent 2.5 ways but they were quite good rather than very good.JBL Studio 590 was one.A lot of speaker for the money.
I do wonder if a 2.5 way using drivers that are more aimed at midrange quality might be better than ones which try to go low.Something like the Troels Gravesen Ekta 25 for example.That could be a really good one.
I do wonder if a 2.5 way using drivers that are more aimed at midrange quality might be better than ones which try to go low.Something like the Troels Gravesen Ekta 25 for example.That could be a really good one.
I can't think of a 2.5-way that looks "identical" to a 3-way or vice-versa. A 3-way has a woofer, a smaller, dedicated midrange driver and tweeter, while a 2.5-way has two identical midwoofers and a tweeter. They are two different ways of achieving higher efficiency and power handling with respect to a 2-way: the 3-way uses a large woofer which, generally speaking, can't reach high enough frequencies to cross it over directly to a tweeter, because of its frequency response and/or directivity, so a midrange driver is needed; the 2.5-way doubles the woofer area by adding a second midwoofer. Each has its pros and cons, but a couple advantages of a 2.5-way is that you don't need a separate midrange enclosure inside de box (two identical midwoofers can happily share the same enclosure without trouble) so construction is simpler, and that you can have a high efficiency speaker with a rather narrow front panel, which maybe what you want for the particular layout of your listening room and/or for diffraction and/or aesthetic and/or WAF reasons.
We don't do it much now but go back 40 or 50 years and drivers of different diametres and such were quite commonly used together in the same box, at least with Japanese speakers. Often no component on the woofers and just that single cap on the closed back cone tweeter. Sometime two closed back tweeters with a larger one treated as a low tweeter/high midrange
My explicit point is that the drivers do not have to be identical, although they may need separate enclosures. It was rabbitz who first made me realise the benefit of the 2.5 Way speaker
That view is quite optimistic.
The 0.5 driver will modulate the output of the midwoofer if they share the same enclosure. Especially in vented designs. You end up with muddy mids with a lot of artifacts. Speaker manufacturers do it, shared volume, because it's cheaper, saves them a few dirhams.
Soundwise it's a bad practice, unless the speaker is an OB one.
I don't mind people doing it, everyone makes their own choices. But I do mind when people insist that it does not matter. Just my 2c.
A conventional 2.5 way will tend to use the same drivers as 2 ways that is a tweeter and midwoofer. The midwoofer is typically 5-6.5" which are common and relatively cheap. An extra midwoofer below the one next to the tweeter helps address the inadequate low frequency output by providing +6 dB to counter the -6dB baffle step loss. This requires a low pass filter on the lower midwoofer to match the baffle step loss. The result tends to be small modestly priced floor standing speakers that are a step up on the equivalent 2 way in terms of efficiency and low frequency output. It's a nice configuration where size and cost are concerns. A 3 way with large woofer/s and dedicated midrange will tend to offer better performance but at a higher price and size.
How? At low frequencies where both drivers are active, both are reproducing exactly the same signal and they are in phase, so they are both pressurizing / rarefying the enclosed air simultaneously... As far as each driver is concerned, it's just as if it was placed in a box with half the volume. Maybe I'm missing something but I don't see where that modulation would be coming from...
Hmm, Moondog, isn't that what I said, to use a separate enclosure? Judging by your photo your 0.5 driver is in a separate box, yes?
cabirio, I think you are missing something. Your theory is OK, but it's just that, theory, my practice tell me otherwise. And I don't want to argue with anyone, just expressing my opinion, so feel free to use them any way you want.