3-way loudspeaker with down firing subwoofer

JCTAUDIO

Member
2019-10-22 8:22 am
Hello everybody,

I wonder if you could help me build my first set of loudspeakers. I work at a furniture manufacturer and I have done a lot of reading about the design of the cabinet. So I have a design in mind that I can build but it needs a down firing subwoofer (like Chario does). I have a limited budget of around €250,- for the components. I know I need a subwoofer, midrange woofer, tweeter and a crossover, but witch sound good together especially with the down firing sub. I live in the Netherlands and soundimport.eu has the most choice (I think) to get components. Witch combo would you use if you look on their site?

If there are already threats about similar projects, please tell me.
 

Zvu

Member
2009-01-15 6:52 pm
Belgrade
Down firing subwoofer needs crossover point to be very low to work really well. 250€ is not enough for 2 subwoofers, 2 midwoofers, 2 tweeters and a pair of crossovers with large inductor and capacitor values if we are looking at Soundimports website.
 
Last edited:

Zvu

Member
2009-01-15 6:52 pm
Belgrade
This would be my take on a low cost down firing three way.

Peerless SLS830667
Buying a Peerless SLS-P830667 woofer? | SoundImports - SoundImports

Low Mms and low Cms tells us that it will not sag in time - which is important factor to look at with down firing sub. It digs deep in vented cabinet and has healthy 8.4mm of Xmax, and some more Xmech i presume, so you should not run out of juice.

With it you need potent midwoofer to be able to cross at say 100Hz - Fountek FW146
Buying a Fountek FW146 woofer? | SoundImports - SoundImports

It is decent performer and should be able to cross low and high enough - around 2kHz.

Tweeter Peerless BC25TG15-04
Buying a Peerless BC25TG15-04 tweeter? | SoundImports - SoundImports

Peerless BC25TG15-04 | HiFiCompass

It is highly underrated tweeter. It measures extremely well and can be crossed at 2kHz without issues even at higher listening volume. It has really good off axis performance - unlike most of SBacoustics tweeters

With these drivers you would end up at around 270 euros for a pair of loudspeakers. How much would the crossover cost is guessing but that must be determined when everything is measured in cabinets. It is one of rare occasions where i'd recommend passive crossover at 2kHz and an active analogue at 100Hz with biamping.
 
Last edited:

Zvu

Member
2009-01-15 6:52 pm
Belgrade
Thanks Zvu. I have an active sub with my bookshelf speakers that crosses over at around 150Hz what feels most natural. So why the low 100Hz? And why one passive and one active crossover?

Active down low because you can set the level of bass quite easily - with a volume knob. All you need to do is make full baffle step passive crossover for Fountek and Peerless.At a price that passive crossover would cost you at 100Hz, you can buy one of the lm3886 kits from ebay and add active analogue to cut it as sharp as you like.

100Hz because i noticed difference listening woofers crossed higher that faced listener and the ones faced at sides. Maybe at larger distance it would not be so obvious (or obvious at all for that matter) but at a couple of meters to me it is. Of course you can cross it over at 150Hz but it will not change the complexity and price for passive crossover to much. And mistakes for passive crossover under 400Hz cost a lot.

Once again, i'd suggest to check TLHP because price difference can be up to 25% compared to other online shops.
 
Last edited:

JCTAUDIO

Member
2019-10-22 8:22 am
Its probably my English but what is a full baffle step passive crossover? Could I use this Dayton Audio XO2W-2K 2-Way Speaker Crossover 2,000 Hz

If I get it right I should make the low part of the speaker similar like my active subwoofer with a build in amp? And connect it with my amp at the sub out?
 

Zvu

Member
2009-01-15 6:52 pm
Belgrade
... how did you find that the SB woofer has resonance at 1.5kHz?

I saw it HERE. There is a hint in impedance graph and there is that lump at 1500Hz but ridge in waterfall makes it obvious.

Its probably my English but what is a full baffle step passive crossover? Could I use this Dayton Audio XO2W-2K 2-Way Speaker Crossover 2,000 Hz

Full baffle step is crossover that will have (in this case) amplitude at 200Hz at the same level as 1000Hz. Very simplistic explanation but if you are interested to learn more about it, there are whole threads dedicated to baffle step effect and how to mitigate it.

No pre-made crossover that you can buy can work well with these drivers. Since you do not posses the necessary knowledge to make your own crossover i would suggest that you use this tweeter:

Tweeter a dome Peerless DX25TG59-04, 4 ohm, bobine diametre 25 mm

You will simplify your life quite a bit because there is a project that is reasonably well documented and uses Fountek FW146 and DX25 tweeter (don't be confused because it says ProAc on that tweeter, it is DX25). Just PM R-Carpenter for details about the cabinets.

follow up on ZA 14 vs Fountek -

Techtalk Speaker Building, Audio, Video Discussion Forum


In that thread there is a crossover schematic. I'm sure that you can get dimensions of that cabinets. If you stick to the width (few centimetres wider cabinet to accommodate 8 inch woofer will not make any substantial difference) and driver placement you're in the game. Adjust the depth of the cabinet to desired volume for Peerless 8"subwoofer. Make a compartment in the upper section of your floorstander for midrange and tweeter (closed compartment, not ported) to separate it from subwoofer chamber in lower section.

If I get it right I should make the low part of the speaker similar like my active subwoofer with a build in amp? And connect it with my amp at the sub out?

Yes, you could do that. It will save the money for active crossover since it is built in your receiver.