Smaller 3-way speakers

[alspe]

When we are speaking of speaker around 20-30 litre box size and for example 6,5" woofer + 1" tweeter they are usually, almost always 2-way speakers. You can combine 6,5"+1" and maybe even 8"/10"+1" in someway but that way drivers should be very good, have to have wide usable frequency response probably 2 octaves beyond the cross over point so usually those drivers are very expensive if very good sound is the main goal. You can use mediocre drivers but can you achieve very good sound then (2-way)? Cross overs must be steep for ensure that tweeter gets no too much lower frequencies and bass driver does not play frequencies where its cone break up might be.

There are quite few 3-way speakers done with 5,25"+3"+1" or 6,5"+3"+1". I heard one cheapish commercial speaker done by that way and it was no bad at all!! IF cross overs can be designed corretly, I think that is reasonble way to design even small speaker. You can choose bit cheaper tweeter if you do not cross it low and you can choose a bit larger woofer if it does not have reproduce mids. Midrange driver should not be able to play highs and lows which are the most difficult for it. Tweeter plays with less distortion if it is not driven to its limits at low end.
You can use 1st or 2nd order xo slopes so drivers integrate better and have less xo distortion.

Thoughts about small 3-ways?

[Zuhl]

Mine are about 35ltr and have a SEAS L22, Morel EM1308 and SEAS 22TAF/G. The crossover is 850hz and 5khz - second order except for the mid low pass which is 1st order. There's also a 1st order high pass on the bass at 60hz to match my sub.

It has seamless integration with impresive detail, depth and ambience. It has a 'rightness' to the sound which is difficult to put into words. I've never had that with a two way.

[mhelin]

Originally Posted by alspe

Thoughts about small 3-ways?

Which drivers would you select and where to cross them over?

How about this set:
- Seas L16RN-SL bass - according to zaph "Typically 25% more Sd than most others in this group. Great harmonic distortion below 200hz, with good extension and good Xmax to back it up." How does the H1488 compare with this driver?

- mid is difficult to choose; I would first try this cheap full range driver:
Fountek FR88-EX . It's got fragile cone but the looks match with the above Seas driver.

- tweeter Seas 27TBCDGB-DXT (just because of the waveguide)

Crossover frequencies I would use with the above would be lowest one close to the baffle step and the upper between 1.5 and 2 kHz. Any comments? Is the waveguide useful in this application when you could cross over at higher? In that case a small neo tweeter could perhaps be the one for this task. Or maybe Vifa XT25SC50 ring radiator starting from 3 - 4 kHz?

[alspe]

Originally Posted by mhelin

Which drivers would you select and where to cross them over?

I have thought of any special yet, just in general. Maybe crossed at where baffle step is (400) and at upper side of ears most sensitive are (3500-5000 Hz).

Seas L16 makes speaker very low sensitive. :/

[whgeiger]

Originally Posted by alspe

When we are speaking of speaker around 20-30 litre box size and for example 6,5" woofer + 1" tweeter they are usually, almost always 2-way speakers. You can combine 6,5"+1" and maybe even 8"/10"+1" in someway but that way drivers should be very good, have to have wide usable frequency response probably 2 octaves beyond the cross over point so usually those drivers are very expensive if very good sound is the main goal. You can use mediocre drivers but can you achieve very good sound then (2-way)? Cross overs must be steep for ensure that tweeter gets no too much lower frequencies and bass driver does not play frequencies where its cone break up might be.

There are quite few 3-way speakers done with 5,25"+3"+1" or 6,5"+3"+1". I heard one cheapish commercial speaker done by that way and it was no bad at all!! IF cross overs can be designed corretly, I think that is reasonble way to design even small speaker. You can choose bit cheaper tweeter if you do not cross it low and you can choose a bit larger woofer if it does not have reproduce mids. Midrange driver should not be able to play highs and lows which are the most difficult for it. Tweeter plays with less distortion if it is not driven to its limits at low end.
You can use 1st or 2nd order xo slopes so drivers integrate better and have less xo distortion.

Thoughts about small 3-ways?

To meet this mission a 2.1 system configuration will yield the most bang for the buck and footprint as well. A powered sub with active crossover will permit a single passive crossover to be designed in the 2-3 kHz range for the satellite drivers; a relatively simple task. The LF driver for the satellites, that now meets a relaxed [xmax] requirement, will be less costly and should reproduce the speech range with enhanced clarity.

Regards,

WHG

[burgunder]

Take a look at these Build Thread: Ardor - point source monitor

[mhelin]

Originally Posted by alspe

Seas L16 makes speaker very low sensitive. :/

Yes but there are no sensitive drivers at that size which were effective in small enclosures. You need higher Qts driver for greater sensitivity but then a large enclosure is must. L16 would be fine if you run it active, on the other hand the mid and the tweeter could have passive crossover and share the power amp channel.

In any case a small speaker will always be less sensitive (full range), it's another story if you limit the bandwidth. Good thing in a small 3-way when compared to 2-way is the lesser IMD. Using more power you can get the increase in output level when IMD stays low. Max. SPL is of course limited by the excursion of the bass driver. There are tricks like a dynamic EQ that could be applied to get more SPL. Satellites + separate woofer is another thing (off topic).

[twest820]

Originally Posted by alspe

Thoughts about small 3-ways?

Hmm, looks like a nude 18 is about 35 liters just by itself. Unless you exclude the interior volume of the driver's cone. So much for that idea. A nude 15 can come in under 20 liters but the SPL gets rather limited.

[alspe]

Originally Posted by mhelin

Yes but there are no sensitive drivers at that size which were effective in small enclosures. You need higher Qts driver for greater sensitivity but then a large enclosure is must. L16 would be fine if you run it active, on the other hand the mid and the tweeter could have passive crossover and share the power amp channel.

In any case a small speaker will always be less sensitive (full range), it's another story if you limit the bandwidth. Good thing in a small 3-way when compared to 2-way is the lesser IMD. Using more power you can get the increase in output level when IMD stays low. Max. SPL is of course limited by the excursion of the bass driver. There are tricks like a dynamic EQ that could be applied to get more SPL. Satellites + separate woofer is another thing (off topic).

Yes, overall sensitivity is defined but enclosure if you want certain bass depth. We must define what is small enclosure. If it 12 litre then L16 might be OK, but in litres I would certainly use more sensitive. Even that bass depth is lost a little bit. L16 8 ohm is around 85 dB/W/m so you must drop mid to ~80 dB/W. I'd like to maintain mids sensitivity, not drop it too much.

At 20 litres ER18 + MCA12RC looks nice combo. Gives 3 dB BSC advantage of woofer, than might be enough if woofer is quite low and wall near. Or even better in 30 litres MCA15RCY + CA22RNY, gives overall sensitivity around 88 dB/W/m which is huge difference compared to ~80-81 dB/W/m.

Active is not option for me right now so any 2.1 satellite system no no.

[mhelin]

Originally Posted by alspe

Or even better in 30 litres MCA15RCY + CA22RNY, gives overall sensitivity around 88 dB/W/m which is huge difference compared to ~80-81 dB/W/m.

Change the mid to MCA12 and you'll get the Classic 3-way:
3-Way Classic

I guess you have seen this design before:
KS-263

This Focal SM9 studio monitor is interesting as it uses passive radiator design:
SM 9 studio speakers. Focal Professional studio monitor loudspeakers

I like the horizontally wider box, would like to try something like 3W classic but in smaller box with similar layout for the drivers as in SM9.