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Mystery speakers, no branding anywhere

Guido57 said:
You can find test items for less than $20 on epay that will give you a good enough measure of the inductors and can also be used for checking capcitors. I think the most expensive single piece of equipment for measuring the drivers is a calibrated microphone. That alone will set you back about a Benjamin or more.
Click to expand...

A calibrated USB mike and some software will measure their acoustic output, but the way to get impedance curves, T/S parameters, etc. is something like DATS from Parts Express. A USB plug in device with alligator clips that you connect to a driver. The software runs a test sweep and gives you all the data. Quite useful for designing a box for a driver, or getting specs on a driver to replace it with something close. $100.

https://www.parts-express.com/dayto...er-based-audio-component-test-system--390-806

Pays for itself if you're going to tinker with speakers in the future, but I agree, probably not worth the investment if you're not.
 
Ok. I may do just that. I did install the new tweeter from parts express. I had to enlarge the opening to accommodate the larger magnet. I have to admit, it does sound better with just the few adjustments I’ve done so far. I will listen for a few more days to see if I like it the way it is right now. I have several sets of speakers I like as a reference. I may tinker a little more with them and see... Thank you for your input!
 
Just FYI, the two yellow capacitor values: one had 12.0J 100v and the other 5.6J 100 v. I’m not sure if that helps figure out the cross over point for the tweeter... Anyway, it sounds like the new tweeters and the woofers are blending in well.
 
to determine any/all/some of the crossover's frequency control
a schematic is necessary.

Those caps may also be used for the bass. look up high/low pass filters using caps.

1) find a schematic for the unit, 2) trace it out your self (follow the wires, draw out the connections/parts)
3) post a really really clear picture (no old phone pictures, use natural light, zoom in close, etc)
and we can help you draw it out.

and if you are going to mod speakers, search for the several sites that have speaker design tools,
learn just a little about crossovers, cabinet specs, driver specs (qt, RF, …).

most folks use tools like sound pressure meters, etc. But nothing to stop you from designing
speakers by ears. I know one incredible SUPER technician who used to go into a large data
center, walk through all those large disk drive systems, and perform routine preventive
maintenance based on need by simply listening to them.

let us know how you do
 
The 5.6 WOULD almost certainly be in series with the tweeter in most speakers. The 12 is a bit of a mystery. Some speakers will have one parallel to the woofer, but it is usually larger than this. Or it may be the 12 is in series with the tweeter, and the 5.6 is in a contour control circuit for the tweeter, and the woofer has no cap. Going to have to generate a schematic to figure this out.

DIYAudioandVideo has some good tools and calculators. If you have trouble tracing out a schematic there are places to find the basic layout and method of drawing them if you need that.
 
So, after tinkering with the amount of foam inside, installed the new tweeter, it actually sounds pretty good. I’m leaving the crossover alone because it is obvious I would not know how to properly alter it to make it sound any better than it it’s now. I’m driving them with an HK avr 8000 which to me, is good pairing.
 

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toxcrusadr said:
A calibrated USB mike and some software will measure their acoustic output, but the way to get impedance curves, T/S parameters, etc. is something like DATS from Parts Express. A USB plug in device with alligator clips that you connect to a driver. The software runs a test sweep and gives you all the data. Quite useful for designing a box for a driver, or getting specs on a driver to replace it with something close. $100.

https://www.parts-express.com/dayto...er-based-audio-component-test-system--390-806

Pays for itself if you're going to tinker with speakers in the future, but I agree, probably not worth the investment if you're not.
Click to expand...
I hadn't seen that item before. Looks a lot simpler than using a microphone, tone generator, mutimeter, etc.
 
Glad the new tweeters are working out for you. If after listening awhile they have any flaws, do post back and we can discuss if there is a straightforward way to attack them.
 
I called TruAudio and asked if they had any specs(crossover) on this particular model but they have not responded and I'm not expecting a response based on the conversation I had with a rep. Maybe in a while, if I don't like something I'm hearing from the speakers, I will ask you for help on how to attack the numbers side of audio. For now, I'm letting my ears and preference dictate my tweaks. So far, a new tweeter and "strategic" foam has made the speakers sound pretty good to me. Both mid-woofers are vented through the magnet as well as the box. I stuffed, and I mean stuffed the box with a lot of foam, which got rid of the mid-range boominess but made it sound muffled and flat and I lost almost all of the midrange from the woofers. I decided to just line the back wall of the upper woofer with the sheet foam the speaker came with and leave the side walls bare. From tweeter down, its pretty stuffed with pillow foam but I kept a channel free of foam for both upper and lower woofers, to allow airflow. You can see the back of the lower woofer through the bottom speaker vent but its pretty stuffed with pillow foam from tweeter down. That did the trick! I got midrange back, no boominess! If I listen from the vents on the back of the speaker, I can tell that the sound coming from the top rear vent is not as deep as the sounds coming out of the lower vent. Anyway, all the sounds coming from the front of the speaker summate to something I like so far! It was fun trying to figure out how to make this speaker sound good to me. I believe the hero in this story are the new tweeters. I think I got lucky that the response curves of the tweeter mates well with the unknown crossover network. Anyway, its good fun!
 
Outstanding!

When you say pillow foam is that actually foam or something more like polyfill?


That's what is recommended for speakers. In fact there is a whole science as to which kind to use - AKers have done some research on that. Parts vendors sell something called Acousta-Stuf that is supposed to be optimal for speakers.

In any case it sounds like you got it dialed in pretty well. Enjoy!
 
I need your help in what direction I need to take in fixing a new issue. I have a Marantz sm-80 driving a synthesis lm-20 through a Sony p9000es pre-amp. It’s happenned twice now. I listen at very moderate volume and suddenly, the sound cuts out and the peak level meters on the Marantz turn on and stay on. I unplug everything off the amp, including power, wait a few minutes, and all is well again.... my question is this: could the speakers or interconnects or the preamp cause this symptom? Help!
 
It sounds like the Marantz is going into protection mode. How long have you been running this configuration? Is it a new problem on a working setup or a problem with a new setup?
 
I have mixed and match my gear over the years. This set up is about a month old. I'd hate to break it up because it sounds really good to me. The gear is getting old... The first time it happened, there was an audible pop then silence. The second time, there was the same pop but the music continued for another 3 seconds then silence. The two peak level lights on the amp turned on and remained on. Would you start at the amp for a fix? Will bad caps on the power stage do this? Will a shorted interconnect cause it to go to protect mode? Could the pre-amp be causing the protect mode? The weird thing is it all works just fine after a few minutes of being unplugged. How would you attack this potentially permanent issue?
 
Most likely it works fine after being unplugged because the protection circuit resets. The Marantz should have plenty of power for these speakers, someone will correct me if I'm wrong. Not likely to be a mismatch with the pre-amp, but can you swap in a different one to check? Here's a link to a page describing a rebuild of one of these units: http://liquidaudio.com.au/marantz-sm-80-amplifier-repair-restoration/ If you're asking these questions you're probably a noob to electronics repair like me. If you are ask yourself if you're willing to go down the rabbit hole of diy repair or is it worth paying an experienced tech to fix it. If you provide your location someone maybe able to point you in the direction of a capable repairman.
 
I am definitely a noob at electronic repair and wil not attempt to fix the electronics! To rule out the speakers as the source of fault, I connected the amp and pre amp to another set of speakers with same impedance rating(8ohms), well that’s what the vandersteen label states. Nothing!! No cut outs just wonderful sound. I listened for over an hour and no problems! The mystery just gets more interesting.... Can deteriorating capacitors on the crossover cause an amp to go into protect mode?
To answers your question about the pillow foam, yes, the sacrificed pillow was filled with similar looking poly fill.
 
If something in the speakers cause them to draw too much from the amp yes it will go into protection mode. Bad caps? Don't know. Open them up and take a look. If they have electrolytic caps replacement of them would standard procedure for a lot of people.
 
I believe I figured it out....I hope. The interconnect from the pre-amp to amp was loose. I could still jiggle them when they were inserted. I tightened them little to make a secure connection. Maybe they were causing a short... Anyway, I saw the overhaul for the Marantz and if I have to go that route, I believe it would be worth it! Thank you again for your input! For now, I’m very content.
 
Glad to hear it. Still worth looking at the speaker caps. I think those speakers are high end enough to have not used electrolytic caps, but if they did you might want to replace them doing one speaker first to see if there's a difference. Wouldn't mind having your setup myself. Good luck.
 
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