Those speakers I bought...

[johnnyrichards]

Bigger box would help. Does Erse still have any bargain 19 gauge 1mH coils left? I got a dozen of them last year and a dozen 18 ga. .6mH too and some more goodies. Geez, those are about like stock B652's with that "hump". I gotta play with the T/S numbers some and see what doesn't help. I have the I.Q. to figure what makes cents. The $12 Vifa sale tweeter would be a real help, but you can't do that.

Bigger box will always help cheap speakers, but not worth it for these drivers.

Similarly, the box is not worth sticking a $12 tweeter in it, without sticking a better woofer in it.

After much deliberation, I decided a $8 buyout woofer, re-using the cabinet with a couple quick mods (two braces, and some fiberglass along the inside walls) with a cheap crossover is the best practical upgrade path.

Of course, upgrades need not always be practical

[Whitneyville1]

I know, I know. How much improvement do I gain at what cost (time, effort, parts)? The "equation" can make no sense at all.

[johnnyrichards]

I know, I know. How much improvement do I gain at what cost (time, effort, parts)? The "equation" can make no sense at all.

That is a question one must ask of any design, regardless of cost.

[Whitneyville1]

Funny you said it that way. To break the reciprocating engine LSR held by the "Goldenrod" since 1965 (409 MPH and change) which cost about $150,000 and took about 4800 BHP took $6.8 million and 6000 BHP to reach 416 and change. (The "one-way" was incredibly fast, but the return trip up the salt was slower than the Goldenrod's return due to engine over-heating. The 411 Streamliner's "record" still hasn't been verified by the FIA yet, as there was more than 10% difference in the two passes, so the Goldenrod's record is still "official".) The old "mo', betta', fasta' " story.

[Wolf]

You talkin' land speed record?

I thought the Thrust SSC held that currently. Beastly dual Rolls Royce jets, and about 800mph...

Yikes!
Wolf

[Sidi]

he said reciprocating engine LSR. not turbo jet engines.

[Wolf]

he said reciprocating engine LSR. not turbo jet engines.

Shows how my hobby is speakers, doesn't it?
Wolf

[Whitneyville1]

I don't think it counts unless you're turning a tire with cylinders, but I'm an old motorhead. Although a steam powered car may have been the first car to break 100 MPH.

[kenrhodes]

Bryan how are those speakers that you got? For the price they look interesting.

[bkeane1259]

Bryan how are those speakers that you got? For the price they look interesting.

I will probably start a gallery thread when I finish them just for kicks. The drivers in that ebay kit are junk, the XO's use NPE's and the MDF with vinyl veneer cabinet has a 1/2" thick front baffle and 3/8" thick material everywhere else. It's NOT a super deal, but like I had mentioned, it's really just an experiment and they are being gifted to a very non-critical listener.

[kenrhodes]

Thats too bad they looked to be ok cabinets in the pictures. Are they set up for a woofer in the bottom or is it all one cabinet top to bottom? would it be worth cutting the bottom out to put bracing in? at least you wouldn't see the bottom when you were done and could add some decent braces.

[bkeane1259]

I don't want to pollute Johnny's thread any more than I already have...go here instead---> http://techtalk.parts-express.com/sh...d.php?t=232181

[johnnyrichards]

Cabinet mods are finished:





I bought a couple 3/4" x 36" poplar sticks at Menards to build the braces. I glued one from front to back between the woofer and tweeter cutouts (this cleared the port by ~1/8"). This brace is a c-hair over 4".

I added a second one from left to right, butted against the front to back brace and resting on the existing glue blocks holding the rear baffle to the sides. This brace is a c-hair over 5-1/8"

At the union between the side walls and the left to right brace, I added a 45 degree glue block, and where the cross brace is butted against the front to back brace I added another 45 degree glue block. The pictures do not show these too well due to the fiberglass pieces I glued all over inside, but they are visible enough to see what I am trying to explain.

I also added two braces, each about 3" long with a 45 degree cut on both ends, tying the left and right panels to the bottom panel. Due to the port keeping things tight I did not add the same to the top.

I used 1" thick paper backed fiberglass on most areas I could reach, and added a small handful (call it 1oz) packed into the top around (but not blocking) the port.

Waiting for glue to dry so I can install the drivers and grab some measurements.

[johnnyrichards]

Five hours of "power voicing" brings me to this point... and I am calling them finished enough. There are around forty songs I listen to in a playlist that I use to "voice" a design, and I am very familiar with each of them. Not sure if I hit what the artist had in mind, or not - and don't really care, either I shoot for a sound that I like. Sometimes it takes a long time, sometimes it goes pretty quickly. A lot depends on how willing I am to doublestitch a silk purse

In any event, not a lot of measurements since this is just a quickie project.

Raw drivers (with grill in place)


On axis and reverse null with impedance:


Distortion at a little over 90db:


Crossover:


The Peerless is pretty typical of the cheaper Peerless drivers. Be advised that if you buy these, they are not exactly new. Both of mine had de-soldered terminals and scarring from being mounted. Nothing to sweat about, since they otherwise appear unused but just something to remember. PE did not mention this in their ad copy.

Neither driver will win any awards, but together they work good 'nough. Distortion remains manageable until over 90db (at 1 meter), so in the near field should appear even cleaner.

No real bass to speak of due to the tuning, so they would be best used with a subwoofer. In a cabinet twice the size, these Peerless would probably do much better.

One more quickie:


The cabinet mods cleaned that up considerably, although I would like to see even more improvements but ain't gonna happen with this project.

Technical Pro speakers: $25

Peerless Woofers: $16

Crossover: $20

Miscellaneous Cabinet mods: $5

Total cost should be less than $70.

Not really worth it unless you just want to play around, or (like me) believe in DIY for the sake of DIY.

[mzisserson]

Golf clap! Looks fun Johnny, definitely worth the time.

[greywarden]

Good work, Johnny! That's right about +/-3dB the whole way! At least you know you and the wife have good ears

[johnnyrichards]

Golf clap! Looks fun Johnny, definitely worth the time.

It is fun, and I think I would have more fun modding or repurposing existing stuff than designing from scratch... That is pretty much how I got started a thousand years ago.

[johnnyrichards]

Good work, Johnny! That's right about +/-3dB the whole way! At least you know you and the wife have good ears

I dunno about me, but she definitely does.

[bkeane1259]

You did a fantastic job turning these around. You make it look easy brutha.

[Whitneyville1]

Johnny, I'm reaching the "point of no returns" on the B652's. I don't have a calibrated mic to test with, but from a pair of stock ones, unless I build new cabinets (much bigger), or spend $$$ on a woofer and tweeter (why not start from scratch?) I think I've made the best cowhide purse from a sow's ear. With Audessey's help they'll make adequate surrounds (not rear left and right mains). The Pioneer's I got on sale from Newegg for $50 a pair make me shake my head. A 4" woofer that goes lower than many 6 1/2" er's at that price.