Building a large Low-Tones cabinet to join existing high quality Compact speakers
 

Hey Y'All!

I'm new here ...never done forums before! First of all I want to apologize for my English (my speach is OK, but I hardly ever need it to write ...so a lot of mistakes and translating!). I'm a Hifi Adept, with very sensible ears, but very few knowledge about speaker mathematics! Mostly while listening to all wellknown and often very expensive speakers, I'll find my stuff! Then getting the right sound by carefully testing and matching pre- and poweramplifiers, cable and interlinks will be the icing on the cake! Having been working for several Hifi Importing companies in Belgium, I own a lot of good stuff, BUT .....I adapt and upgrade most of it ...when should you be completely happy!?

Sometimes you don't find what you are looking for (or it may be way too expensive). As I have several very, very,very good Compact Speakers (Monitor Audio, Dynaudio, Spendor) I never invested in Big speakers, because I feel they don't do Highs an Mids as good as the compacts! I tried a lot of high quality Subwoofers, but NEVER found it completing the sound ...it just added something not coherent! I play almost any kinds of music (this is why I use several speakers)

So here's the question :
Would it be a (good) solution to build an enclosure of about 100 up to 150 liters, to put in 1 or 2 bassdrivers, which don't play uniquely subbass, but work up to maybe 200 or 300 Hz, and with a filter (Highpass?) that is variable and let the Compacts only play Highs and Mids and then nicely pass over the job?

If I'm right, it would be like the lower cabinet of a separated speaker (seen several High-End speakers that way and also building projects). MONACOR has something like that : the MENHIR ...so could I use such a kit, or build alike with higher quality components?

I also saw from Monacor the SAM-2 amplifier, which seems to do such a job (if I go from my preamplifier to the Sam-2 and from there to the poweramp, it cuts the Compacts up to 150 Hz).This would be an active solution?

So the question stands, and most important is a real high quality blending (active or passive ...I'm still a bit oldfashioned so I won't think about digital variable and/or programmable stuff!) with different Compact speakers! (and playing and testing)

As I'm 'new' in this part of the market, my idea may be ridiculous, very easy, complicated or not possible with a good quality wanted, but I'm excited anyway to see if I will be combining two worlds! (mostly people who buy expensive stuff, just listen, don't touch, and are willing sheep to get slaughtered by commercial guys ...people who build on a decent level, will want to build everything themselves from A till Z!).

Thanks in advance!

Crossing over at 200 to 300 cycles needs a lot more fine tuning to accomplish a smooth crossover and alignment from the lows to the mids than the more usual "sub" crossover around 100 Hz, below most vocal range.
Crossing at 200-300 is right in the middle of the vocal fundamental range, if the transition is not really smooth, the speaker system will not sound very good, even though it has more LF extension.
Bass reflex or sealed will make the transition the easiest, but by far the hardest part of the project is the crossover.
To "do it right" you need to cut the lows out of the high speakers as well as the highs out of the lows.
This is not a matter of simply putting a few capacitors, coils and resistors together.

Alignment is by far easier to do with DSP than passively, especially if you don't have detailed impedance curves of all the drivers.

If you want to do the crossovers passively, there is a good sticky about building passive crossovers without measurement at the top of the full range section.
http://www.diyaudio.com/forums/multi...asurement.html

Good luck!

Your small monitors will work to around 60Hz at least, so I would suggest crossing over much lower than you intended.

The Monacor Menhir is a very different speaker than the one you describe. That one is a regular 2way PA style speaker with a 2000Hz crossover point not a woofer + mid-high unit.

You will probably need to get a pair of the best possible subwoofers money can buy to get a good match with a pair of top class mini monitors.

If you were in the US I was going to recommend a pair of JL Audio f112 Fathoms or try to build something similar using JL Audio 12W6 or 12W7 drivers but since you are in Europe look for Peerless XXLS, Dayton, or SEAS top of the line 12" or 15"subs. Pair them with good plate amps and you may get there. Also if you are brave enough look at TC Sounds and RE audio subs if you don't mind braking the bank.

OK weltersys, vacuphile, spirosZ ...gratefull for the input! I'm adapting my view already about crossing over (red some about the freq.range of human voice and critical range) and I may build a heavy, well braced towerlike cabinet as a sub, with a good amplifier, based on 2x12" drivers. I looked at them all : Peerless, Seas, ScanSpeak, JL Audio, TC Sounds, ...about 280-4OO euro per driver should get me there (I first will read all the tests I can get my hands on!).

I'll try it out with Compact monitors ...do I get the right sound, then I build a second one for Hifi ....am I not satisfied, then the sub goes to the surround system (which need another sub anyway!).

I also glanced at the thread about building crossovers ...interesting! Will study it! Just red the book of David B. Weems ...ordered 3 Visaton brochures and book, two Monacor LS building brochures and the Loudspeaker Design Cookbook of Dickason (Salute! to the Internet!). I also may get the book from Joe D'Appolito! I'll be armed ...and try to get dangerous! ...learn about filters!

Another question :

For now, knowing it's purpose, with an enclosure of about 100-130 liters, would I use 1 driver, 2 identical active drivers or 1 active and 1 passive driver and will I get the best Hifi sound with a closed or BR enclosure?

See y'all!

For HIFI I would say two (left-right) active closed boxes.
As to frequency, they should start at 27,5hz. (one of the reason for the 'active' part)
That's the lowest note on a grand piano. But this depends on your music taste.
If you want to go the organ route, your in trouble (16hz or even 8hz!)

Hey Bart,

Yes, 2 active boxes is what I will build, and 27,5 Hz is good enough (I love Piano and Harp / I don't like Organ in general, but will play some Albinoni (Adagio), and Zarathustra only for demonstrations) ...But then the question is whether I will use in each enclosure :
1 active driver
1 active + 1 passive driver
or 2 active drivers ?

Driver count, size, and Xmax are dependent on your desired SPL.
Some members here desire 120 dB at 20 Hz, others are satisfied with 95 dB at 30 Hz.

A pair (two cabinets) of sealed long throw 12" (around 13mm Xmax) should take care of your needs.
If you go with larger, low tuned (20-30Hz) you can get by with less than half the power required for sealed, and may not need compensating EQ.

My personal preference, when price is not as important, would be to use two drivers per closed cabinet and active filtering between mains and subs. So active all the way. I can't comment on driver choice. To much variables and subjective comment on the net.
Even if you don't want furniture shaking effects, it's good to have a lot of headroom for compression's and distortion's sake.
If you go the bass reflex route and tune at 27,5hz, the drivers will have less strain and you could go with one driver per box instead of two, but the box will be about the same I guess.

Basically the same comment as weltersys, only difference is, he really knows what he's saying, I'm just repeating from memory. :D