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Multi-Way Conventional loudspeakers with crossovers

400-2025 Optimus-T100 Speaker
400-2025 Optimus-T100 Speaker
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Old 14th June 2006, 08:28 AM   #1
DavidK2 is offline DavidK2  Canada
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Join Date: Jan 2006
Location: in a house
Default 400-2025 Optimus-T100 Speaker

Hello All, I have been reading and searching for quite some time now and cannot seem to find exacty what I am looking for. The above mentioned speakers are what I have to work with. From the website:

400-2025 Optimus-T100 Speaker

Power Input: 75 Watts max
Frequency Response: 55 Hz to 18 kHz
Impedance: 8 Ohms
System Resonance: 55 Hz
Cross-over Point: 3.5 kHz
Enclosure Type: Oiled walnut veneer sealed for extended bass response
Control Type: Tweeter level control
Enclosure Size (HWD): 36" x 13" x 12 1/2"
914.40 x 330.20 x 311.15 mm
Woofer Size: 8"
Woofer Type: Acoustic-suspension with brass voice coil
Woofer Magnet Size: 10.1 ounces
Tweeter Type: Extended range high compliance

So these things have 2, 8" drivers, a tweeter and a volume control for the tweeter, which I figure is an 'L' Pad, in each cabinet. They are in quite sad shape. Having rescued them from certian destruction by way of the garbage man in 1998. Someone had replaced the original tweeters with Realistic Cat # 40-1278B 8 ohm. Don't have any specs on this at all. I replaced the blown 8" drivers with some great Canadian made Cambridge Speaker's Crown Series 800 woofers. I have all the specs on this, Freq resp 30 - 2.5K, Fs 38Hz, 8 ohm, 80W, etc. Didn't work so well. The problem, I figured, was the impedence offered to my amp with the woofers wired in parallel caused the amp to distort and shut down. So I wired the woofers in series and called it a day. Still didn't like the sound. Put them away, and there they sat. So I bought a place and need some sound in my computer room.

So I hooked them up and still really didn't like the sound. Tweeters sound too loud, woofers try to make midrange and bass. Sounds like bad Karaokee, the music is playing, but no one is singing. No voice. Ah Ha, I say. Need some midrange. And while I'm at it I need a crossover. Mabe I need a doctor. So I go and buy a pair of 2000 Acustics 8 ohm 100W sealed back 4" midrange speakers. No specs, all it has is 89-240 on the sticker. Price was right, 22.50 CDN/driver. I also picked up some el-cheapo crossovers. Nippon America 3 way crossover network model 801. max power 150W, crossover freq 2.2K, 5K, 8 ohm impedence.

So I have all this stuff to make some better sound out of some really old, beat up cabinets. Well you can't see sound right? So who cares what they look like lets make some sound. I routered out the hole where the tweeter was to make room for the midrange, and plan on mounting an as of yet to be bought 3" soft dome tweeter. Now come the questions.

1. How can I make 2 woofers work off the crossover?
2. The output of the crossover is looking for 8 ohms, not 4 or 16. Is it possible or even practical to build an impedence matching circuit to compensate for this?
3. If so how? The designs and software I have found only take into consideration 1 driver for each band. I'm not afraid of the math. But would I treat the two woofers as one 4 or 16 and go from there?. The amp is rated 100W into 8 ohms per channel, so it goes back to matching the impedence of the crossover to the amp.
4. Or would it be better to design and build a custom crossover with 2 identical sections for the 2 woofers, one for tweeter and one for midrange. In essence a 4 way cross for a 3 way speaker.
Ya, I know, reading all this makes my head hurt too. Where is that doctor anyhow? Sorry if this was a bit long, I appreciate your time to read this and hopefully point me in some direction other than the cliff I am walking over.

David K

PS:I have pictures of the mess if you are interested.
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Old 14th May 2008, 11:03 AM   #2
johnny18 is offline johnny18  United Kingdom
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Join Date: May 2008
Default speakers

hey i saw ya looking 4 information on the omtimus t-100 speakers ive had a set 4 4 a while ive sanded them down n restaing dem and ive got 4 400watt speakers on the way n a horn tweeter 200watt but ive drilled a hole in da bottom of da wood n put a bass funnel in it n rewired all the crossovers n they will sound gr8 with any powerfull basspins as long as u have a bassfunel 2 let air out n the crossovers r onli relli gd 4 the tweeter n if u need any imformation on dem im ya man m8 cheers john
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Old 14th May 2008, 11:17 AM   #3
Netlist is offline Netlist  Belgium
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Join Date: Jan 2003
Euh..and in plain English? Without netspeak and with correct punctuations and capitalisations?

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Old 29th March 2011, 11:15 AM   #4
Evo4Jon is offline Evo4Jon  United Kingdom
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Join Date: Aug 2004
Location: north west England
Johnny18, I noticed a type error in your post mate:
"a while ive sanded them down "

It should have been "a while ive sanded dem down"

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