loud depends a lot on the drivers you are using.
I dont think the SEAS drivers will go too loud.
also LOUD will be limited to the upper bass after that in the low bass excursion limitation will set in unless u use a sub.
below are details of my existing system.
My project had simple parameters.
1. capable of high sound pressure levels from 40Hz - 20,000Hz. Many speakers cannot produce high sound pressure levels at low frequencies and at high frequencies tend tend to sound shrill at high SPLs I wanted to correct that.
2. Decent imaging in vertical and horizontal plane from my listening position
3. not to occupy too much space and to be flexible to be converted into other rooms.
4. Simple to build and design as I do not have any software or measuring instruments and find all that work to tedious to begin with.
5. economical.
Since I wanted a simple system I targeted building a bi amp system. The bi amp system would have 2 parts. 1 bass less than 60Hz and the 2 main system.
BASS:
The bass was built using 2 12" woofers (per channel) from Audio Concepts (
www.audioc.com). At that time the best woofers I could get from them were the DV12 (dual voice coil) now the SV12 is supposed to be better as well as other drivers like the Hsu and Shiva. I got these drivers in a special sale at $98 each. Each driver could operate in as little as 2.5 cu. ft but 3 cu. ft. was a bit better.
Hence I built 2 boxes 30" wide, 24" deep and 18" high. These would sit on the ground like large coffee tables. I decided to fire the woofers backwards (towards teh rear wall) so that the woofers cannot be seen. Pleae note that large woofers with heavy cones like the DV12 should not be fired downards as the spider gets streched and over time the bass limit reduces.
In between these coffee tables I have 2 chairs where I normally sit to read my newspaper, office work and other serious reading.
The box (except for the baffle) was made of a sandwich using 18mm MDF and 2mm Lead. Hence the box walls were 38mm thick. After the box was made (no baffle yet) I took fiberglass cloth and layered the box walls with cloth as poured polyester resin on this cloth to create a 3-4mm thick liner inside the box (on the walls). Hence the box walls were now 42mm thick. Then I loosley filled 5 kgs of glass wool per box. The baffle (30" x 18") was made using 30mm MDF reinforced with 50mm x 50mm solid wood 6" apart along each dimension. Hence there were 4 reinforements in one direction (30" direction) and and 2 in the other.
The 2 woofers were mounted side by side and are powered by a Carver M1.0t amp.
MAIN SYSTEM:
The concept of the main system came becuase I wanted a system to handle large ammounts of power and yet have little distortion. For simplicity the system had to be a 2 way system. hence I decided to use a MTM.
The drivers chosen were part by accident and part by looking at all specifications. A MTM is best with either 5" or 6" woofers (although I had built a MTM using 2 8" Focal woofers caleld 8N515 and a 1" Morel tweeter called MDT33).
Combinations I looked at were....
Dynaudio 15W75 and D260 (also called Gemini)
Dynaudio 17W75XL and D260
SEAS Excel 17cm and Excel tweeter
Focal 7K415 and Focal T120tdx tweeter
Scan Speak 18W8545 and 9900
Scan Speak 18W8546 and 9900
each of these were rejected because of one problem or the other. The 15W75 and SEAS Excel had limited capability in low frequency sound repssure levels (the 15W75 had limited Sd and the SEAS Excel had limited Xmax). The Dynaudio 17W75XL had some matching problems and the Focal 7K415 had uncontrolled kevlar sound in the 1-3k region. The D260 was not as good teh Scan Speak Revelator, the Focal tweeter had a foam surround giving it limited life, etc...eventually the decision came between the Scan Speak 8545 and 8546 woofer and 9900 tweeter. A friend had 4 8546 wooofers and 2 9900 tweeters he had got cheap as demos and sold them to me at $60 per tweeter and $40 per woofer. So I got lucky. For $280 I got all my main drivers.
The box on the main system was built using a home made version of B&W's matrix box. I took a box made of 18mm MDF and using 3mm MDF made a 4" x 4" mesh of wood that was inserted in the box. This is a very tedious process.
Each box was 20" high, 8" wide and 22" deep. Each box was then filled with about 1 kg of glass wool.
I built a seperate crossover box about 8" wide, 4" high and 22" deep.
The XO box was kept on the SUB and the Main speaker was kept on the XO. However I found that the system was too low. The tweeter was only 32" from the ground. by adding books from my encyclopedia collections I realised that the best height for me was withh teh tweeter 40" from the ground. Hence I rebuilt the XO Box.
I built a 12" high stand. Then placed the XO components around the vertical pillars of the stand and then built a box (5 sides) around the XO components.
The passive XO between the 8546 and 9900 is also very simple.
It has to do 4 things.
1. make impedance relatively flat
2. protect tweeter from low frequencies
3. roll of high frequncies from midbass to prevent beaming and suppress upper midrange cone resonance
4. compensate for difraction loss
the tweeter crossover is as follows.
1. series capacitor (6.7 uf using 2uf wonder cap and 4.7uf polyester cap in parallel)
2. parallel inductor (1.0mh air core inductor)
3. series resistor try values between 1 and 2 ohms
4. parallel resistor try 10 ohms - 16 ohms.
1 and 2 are the crossover you can try various values. remember if inductor is small then the Q of the corssover goes up. I prefer the sound of low Q crossovers hence I use big inductors.
you can try values between 5uf and 10uf for the capacitor and 0.4mh and 1mh for the inductor.
3 and 4 protect the tweeter and also reduce the level of the tweeter by about 2db. I use 1ohms series and 16 ohms parallel. you can try other values
The woofer corssover is as follows:
1. series inductor paralleled with resistor - 1.0mh and 3.3 ohms
2. 0.43mh series inductor
3. 10 uf polyester capacitor
1. is the difraction compensation. this system does not require too mcuh difraction compensation as the bass part (till 100hz or so) is being compensated by the sub. Again I prefer to use guidelines and work between these.
for difraction compenstion circuit you can try inductors from 0.6mh to 1.2mh and resistor from 2ohms to 4 ohms. infact I tried resistors from 1ohms to 10 ohms to see the difference.
Hope this helps.
Love
Navin
