Speaker replacement possiblities

[Jackal2k3]

I have a couple 3-foot Realistic speakers, circa 1977 or so. They have two 16 ohm 8 in woofers and an antenuated 8 ohm tweeter all in parallel per box. I have some specs for the tweeter but i cant find any information on the woofers as far as thier rating goes. The boxes come out to about 2.4 cu.ft.
The problem i have is that one of the woofers is not making good sound. It fuzzes a bit on the lows.
I was looking at replacing two of the woofers with these http://www.partsexpress.com/pe/showd...number=299-134
8in, shielded, 16 ohm 70W RMS/100W max
I was figuring replacing one woofer per side would leave the system sysmetrical and solve my blown speaker problem.

I'm powering all this with a Realistic SA-2000 which is from about the same year. It may have all been purchased as a set. I'm not sure what the actual power output is on the amp, but i believe it's 70Wx4(RMS i think). As far as i can tell the amplifier is VERY clear and makes very good sound on the box with good speakers.

My main concerns here are whether or not this new speaker will meet the sound quality of the old ones, Whether or not there is a better configuration for the speaker wiring and ratings, and what the best way to get a good sounding box with about 4ohm's over all impedence is.

I'm not a complete n00b here. I have an ear for good music and sound quality and can put together just about anything.
I'm looking to keep costs as low as possible. Any help would be appreciated.

Thank You,
tanner powell

[richie00boy]

I think you are taking a bit of a gamble as the new drivers sensitivity and high frequency behaviour will likely not match the old units. Also you really need to replace all four units with the same.

That's before we even get to the Thiele-Small parameters probably being different and so the bass response will be different, and the box will have to be sealed for those drivers. They won't give you all that deep bass either but it will be a little peaked, probably suit the 70s sound quite well.

[Jackal2k3]

I just found these also http://www.mcminone.com/product.asp?...5&info=details
Speaker Size: 8 , Power Handling: 60 W RMS/100 W Peak, Voice Coil Diameter: 1 , Frequency Response: 30~5 KHz, Magnet Weight: 18 oz, SPL: 87 dB, Fs: 34 Hz, Qts: 0.72, Vas: 3.12 cu. ft.

I really dont know where to go with this. If i replace all four speakers and they are woofers with say 30-5khz response, is it pretty safe to say my tweeters that respond down to 3khz will overlap ok and sound decent throughout full audible range?

[sreten]

Hi,

Hmmm.... replacing all 4 sounds a lot worse to me than 1 a side.

Specs of the driver posted are not promising, Qts is too high.
If the speakers are vented they are even less suitable.

Really need more info about the crossover, are they MTM, TMM.
If TMM is the crossover 2.5 way, if so replacing the two bottom
bass units may be an option.

2.4 cuft internal is a big box, are the bass units seperately loaded ?
Sealed or vented ?

/sreten.

[Jackal2k3]

its a sealed box, mdf with oak exterior. Its open top to bottom with some fiberglass insulation in the box.

Not sure about the crossover terms you are using. What is TMM and MTM? I dont think it has any kind of crossover on the box itself. Just an atenuator on the tweeter.

I think i understand now. Its TMM i believe. Witht eh tweeter on top and then two bass units below.

Might i be better off running two 8" 4 ohm woofers in series on each side and run that in parallel with the 8 ohm tweeter? Would there be a power loss there?

[sreten]

Hi,

presumably its a capacitor on the tweeter, (needed at least),
if attenuation there would then be additional resistors.

Tweeter on top then bass/mid then bass/mid bottom = TMM.
Bass/mid on top then tweeter then bass/mid bottom = MTM.

The MCM driver is a lot better. To be honest though its still
a lottery. If you want a quick and dirty fix get 2 of the MCM
drivers, will probably work fairly well.
loading will be 8 ohms, not 4.

The other options are a lot more expensive - what info do
you have on the tweeter, reuse may be possible with two
new bass units per side (for 4 ohm loading) and a proper
crossover for the units.
sounds like the box would need some bracing also.

/sreten.

[Jackal2k3]

The tweeter: 8 ohm 2KHz-18KHz 7w nominal 15w max, and i belive its sealed.
You're right there is a cap on the tweeter. I cant really read the specs except that its made by ELNA and a 50v. It also has a knob that i belive is an attenuator. It is labeled as an optimus t-100 and marked with AT-40H L - 8ohm 60

The box may need bracing but i doubt it. Its all 3/4 MDF with a 1/4 in oak veneer. Do you mean the speakers will need to be seperated?