Odd 4 woofer speakers. Possible white vans?

[dcbk]

Re: Odd 4 woofer speakers. Possible white vans? [KLH Model 488]

More info, the woofers are 4 ohm (measured with a volt meter 4.5 ohms). Replacing with Goldwood GW-208/4 8" OEM Woofer 4 Ohm Part # 290-310 like these http://www.parts-express.com/goldwood-gw-208-4-8-oem-woofer-4-ohm--290-310

Goldwood GW-208/4 8" OEM Woofer 4 Ohm
These low frequency OEM drivers are ideal for the customer who is looking for inexpensive replacement woofers. Each woofer features a treated poly-laminated paper cone, vented pole piece, moisture resistant poly foam surround, and stamped steel frame.


PRODUCT SPECIFICATIONS
Nominal Diameter 8"
Power Handling (RMS) 100 Watts
Power Handling (max) 200 Watts
Impedance 4 ohms
Frequency Response 45 to 7,000 Hz
Sensitivity 88 dB 1W/1m
Voice Coil Diameter 1.5"
Magnet Weight 20 oz.
THIELE-SMALL PARAMETERS
Resonant Frequency (Fs) 51.5 Hz
DC Resistance (Re) 3.7 ohms
Voice Coil Inductance (Le) 0.4 mH
Mechanical Q (Qms) 4.11
Electromagnetic Q (Qes)0.85
Total Q (Qts) 0.7
Compliance Equivalent Volume (Vas) 0.81 ft.³
Mechanical Compliance of Suspension (Cms) 0.38 mm/N
BL Product (BL) 5.93 Tm
Diaphragm Mass Inc. Airload (Mms) 24.9g
Maximum Linear Excursion (Xmax) 3.5 mm
Surface Area of Cone (Sd) 205.9 cm²
MATERIALS OF CONSTRUCTION
Cone Material Treated Paper
Surround Material Foam
Magnet Material Ferrite
MOUNTING INFORMATION
Overall Outside Diameter 8"
Baffle Cutout Diameter 7.125"
Depth 3.69"
# Mounting Holes 4
OPTIMUM CABINET SIZE (DETERMINED USING BASSBOX 6 PRO HIGH FIDELITY SUGGESTION)
Sealed Volume1.5 ft.³
Sealed F3 65 Hz
Vented Volume 2.38 ft.³
Vented F3 34 Hz
GOLDWOOD GW-208/4 8" OEM WOOFER 4 OHM
Brand Goldwood
Model GW-208/4
Part Number 290-310
UPC 643420100419

 

[budgetaudio6]

Good to see this thread. There was virtually nothing on the web when i started asking about them...now there's this thread with photos.!

 

[Mikerodrig27]

I just got a set of these (KLH model 488 I assume) but there was no model tag on them. I do have the original speaker guards which have the KLH logo on them. I picked them up at our local waste and recycling center where there is a tent set up to sell used goods. I got them for $15. All of the speakers work perfectly.

They sound great! They sound better than my B&W V202 speakers that I got for free at that same recycling center. The craftsmanship on the cabinet isn't the best but they are built out of what seems like 3/4" material. The tweeters weren't installed square. The foam that was originally installed seemed to have fallen to the bottom and the woofers on the rear of the cabinets showed fading from some kind of sun damage. Also, the laminate has swelled in some areas and the fasteners had a ton of surface rust.

I decided to do sort of a tear apart and refurbish a few things. took all of the speakers out, labeled the wires and pulled the crossover. I then went to Wal-Mart and picked up some mattress topper to reline the cabinets with foam material. I decided to do the sides, top and bottom. I brushed on some contact cement to the speaker only and installed the foam with the contact cement wet. The contact cement soaks into the foam and the air in the foam dries it. If anyone decides to do this the measurements I used for the foam on these speakers are

Sides: 37.0"x9.25"
Top/botton: 8"x9.25

Next I wanted to address the multicolored sunfaded speaker issue. I decided to pull out an art brush and some black paint. I used spray paint because it is a lot thinner and less likely to change the weight of the cone if that matters. I just sprayed it into a plastic cup and dipped the brush into that. The paint I used VHT Roll Bar and Chassis spray paint. I used it because I had it on hand but it is by far my favorite spray paint. It's never dissapointed me.

Both of these woofers were the same color before I put a coat of paint on them"

I decided I'd just do them all:

Lastly I wanted to address the fasteners being rusty. I have a bunch of screws from some other speakers that I have torn apart in the past. Alot of them were hex head. They had some rust on them as well so I took the screws from these speakers as well as my other speaker screws and threw them into a bowl filled with phosphoric acid. This stripped all of the rust off. I then rinsed dried them and sprayed them with my VHT paint.

When I installed the speakers I used the hex head screws on all of the woofers and normal phillips on the mid and tweeters.

With the added foam, the speakers sound a lot tighter. They still sound natural but clearer and smoother. I'd recommend anyone to add mattress topper to the speakers.

It got late and even though I put them all back together I need to get a semi completed pic for you guys. I still want to figure out how to squish the laminate back but other than that they are a hard core set of speakers for a total cost of around $30 (matress topper and speaker price)

Some reference pictures for you guys:

 

[toxcrusadr]

Nice!

For a couple bucks you could replace that cheap nonpolar electrolytic cap in the crossover with a nice film cap. But if you like the way they sound, they're probably not so old that the cap is in dire need of replacement. Just seems like something you'd want to do since you put all the effort into everything else.

 

[Mikerodrig27]

I'm interested in trying that. I like the way they sound but wouldn't be opposed to trying something new. This is a hobby anyways.

I was hoping the Dayton film caps from Parts-Express would have been a good option but their caps start off at 200v and none of them are 4.7uF

Is it weird that the crossover only has three components? My two way bookshelf crossovers are more complicated then that.

 

[toxcrusadr]

There is no problem using a higher voltage rating, you just shouldn't go lower. I am surprised there is not a 4.7. However, you can parallel caps to get the correct value.

 

[toxcrusadr]

There are metallized polyprop capacitors by Dayton in 4.7 uf, both 1% and 5% tolerance.

 

[toxcrusadr]

As for the number of components, a simpler crossover is not necessarily better or worse. It all depends on the rest of the design - cabinet and drivers. On the other hand, a lot of inexpensive speakers got that way because compromises were made to reduce the cost of parts, including making very simple crossovers. However (in case you're tempted), it's not that easy to re-engineer a speaker, even a cheap one, so 99% of the time you're better off updating what's there with fresh caps and leaving it at that. Usually replacing the tweeter cap with a newer higher quality one pleases most people.

 

[tensleep]

I love cheap speakers - great job on the refresh!

 

[llanger]

This is one of the most interesting threads I've read on Audio Karma. I can't believe I perused every post...4 woofer, rear dual ported speakers...pretty interesting design. I think the speakers look cool.

 

[RedSquare]

Great bump and refurb job. Also, I love VHT products too. Used their epoxy primer on my mini truck's diff/axle.

 

[seditionary]

L-Pad

They sound great! They sound better than my B&W V202 speakers that I got for free at that same recycling center.

Awesome work! I like these speakers too. The bass is INCREDIBLE. I guess it should be with 4 woofers per side, huh?

Have you found the tweeter to be a bit bright on them though? Almost seems like the tweeter & driver are a bit bright on mine... I am still thinking of trying to build an L-Pad into the tweeters. As you wouldn't build one into the driver as well, right? Or whatever you call that second speaker down -- the driver, no?

If I decide to try to dampen the brightness on the tweeter --

It isn't as simple as a single series resistor to the plus though, huh?

What values of resistors should I use? From reading about it -- There should be a series resistor to the + and another resistor connected from the + series resistor to the -?

Is that correct? What are the recommend values for the + Series resistor as well as the shunt resistor that goes from the + to the -?

Thank you guys for your guidance

 

[Mikerodrig27]

There are metallized polyprop capacitors by Dayton in 4.7 uf, both 1% and 5% tolerance.

As for the number of components, a simpler crossover is not necessarily better or worse. It all depends on the rest of the design - cabinet and drivers. On the other hand, a lot of inexpensive speakers got that way because compromises were made to reduce the cost of parts, including making very simple crossovers. However (in case you're tempted), it's not that easy to re-engineer a speaker, even a cheap one, so 99% of the time you're better off updating what's there with fresh caps and leaving it at that. Usually replacing the tweeter cap with a newer higher quality one pleases most people.

If I had to guess I would say the manufacturer was looking to make an inexpensive crossover. It kind of looks like these were slapped together. The rubber pieces on the cabiner that the studs on the speaker grills fit into were pushed into the cabinet so hard that it blew out the wood on the inside They made up for it by being really cool and having a ton of speakers. I don't plan on remodeling the crossover other than adding the capacitors. Maybe if I get the itch, I'll re-read that crossover thread at DIYaudio and try some mods that are reverseable.

I love cheap speakers - great job on the refresh!

It's always more satisfying when you know you didn't spend hundreds to thousands on something!! I'm a bargain hunter at heart. I'll sort through all kinds of messes to find something cheap and cool.

Great bump and refurb job. Also, I love VHT products too. Used their epoxy primer on my mini truck's diff/axle.

Thanks, VHT makes a heck of a paint. They are expensive but there is no guesswork with them. I've never had to redo a paint job with VHT stuff.

Awesome work! I like these speakers too. The bass is INCREDIBLE. I guess it should be with 4 woofers per side, huh?

Have you found the tweeter to be a bit bright on them though? Almost seems like the tweeter & driver are a bit bright on mine... I am still thinking of trying to build an L-Pad into the tweeters. As you wouldn't build one into the driver as well, right? Or whatever you call that second speaker down -- the driver, no?

If I decide to try to dampen the brightness on the tweeter --

It isn't as simple as a single series resistor to the plus though, huh?

What values of resistors should I use? From reading about it -- There should be a series resistor to the + and another resistor connected from the + series resistor to the -?

Is that correct? What are the recommend values for the + Series resistor as well as the shunt resistor that goes from the + to the -?

Thank you guys for your guidance

I haven't found the tweeter to be bright. I like high frequencies in my music. Maybe my room just drowns them out or something but I've actually increased the treble slightly.

Read this thread if you want to understand the crossovers.

http://www.diyaudio.com/forums/mult...designing-crossovers-without-measurement.html

Luckily, these are very simple crossovers so they may be easy and fun to modify a little bit.

 

[Mikerodrig27]

Oh, I ordered the caps from PE tonight. I got the 4.7 1% caps that tux suggested. Thanks tux for bringing the cap thing up as I wouldn't have thought of that.

 

[tensleep]

In my experience, good capacitors in crossovers make a big difference. I have used Daytons on some modified Bozak crossovers, to great effect. And, in keeping with your theme, it is one of the biggest bangs for the buck.

 

[soundmotor]

I likely have more Celestion content than those speakers do.

 

[seditionary]

I likely have more Celestion content than those speakers do.

I like The Residents.

 

[seditionary]

I haven't found the tweeter to be bright. I like high frequencies in my music. Maybe my room just drowns them out or something but I've actually increased the treble slightly.

Read this thread if you want to understand the crossovers.

http://www.diyaudio.com/forums/mult...designing-crossovers-without-measurement.html

Luckily, these are very simple crossovers so they may be easy and fun to modify a little bit.

So the L-Pad happens where the cross over is? Or is that just a separate statement about the cross overs?

Anyone with thoughts on what value resistors to use to dampen the tweeter a bit?

What amp are you driving the speakers with, Mike?

 

[CH46E]

I was looking for a set of those for a long time. They look just like the KLH sold in Costco in the mid to early 90's. Id still pick up a set if I had the chance.

 

[Mikerodrig27]

So the L-Pad happens where the cross over is? Or is that just a separate statement about the cross overs?

Anyone with thoughts on what value resistors to use to dampen the tweeter a bit?

What amp are you driving the speakers with, Mike?

If you hook the L-pad up to the tweeter part of the crossover, it will lower the sound level of the tweeter while not changing the impedance of the driver thus not having a large effect on the way the crossover works.

If you feel that the tweeter is too agressive then I'd try reducing the sensitivity by 3db. Maybe grab a couple of resistors in different values since they're cheap anyways.

"The resistor
If you subtract the woofer sensitivity figure from the tweeter sensitivity figure, you'll have a starting point for how much to lower the tweeter's level. Lower it a couple of dB more for good measure, if desired (there are several reasons for wanting to try this).

To choose the value of resistor to use, look at the following. To attenuate the tweeter by 1dB, take the tweeter impedance value we've been using here and multiply it by 0.12 to get the resistor value. For 2dB multiply instead by 0.25, 3dB by 0.4, 4dB by 0.6, 5dB by 0.8, and finally for 6dB of attenuation use a resistor which is equal to the impedance value.

You'll likely tweak this later, it is a very commonly adjusted component."

For the amp, I'm using a 5ish year old Onkyo AV receiver. It seems to work pretty well. It can definately get them loud enough for my taste. I'm also coupling them with a custom 15" ported subwoofer that I have. The KLH speakers handle anything down to 60ish hz and anything below that is in the subs territory.