First DIY project not working (potential XO problem?)

[sorue]

i just 'finished' my first diy speaker project, but it didn't turn out as expected. i went with the zaph zrt 2-way kit from madisound, with pre-assembled crossovers. After hooking everything up, there was only sound coming from the tweeter, but no sound at all coming from both speakers' woofers. Like the XO wasn't working.

I'm using an external XO box.



All wiring is either canare quad 4s8 / 4s11. Each speaker is connected to the XO box by 4 pole speakons with female speakon (2m) cables connecting them together. Tweeter terminals have quick connects; woofer terminals are soldered.

I was wondering if it could be my poor soldering skills that caused a cold joint somewhere, but i checked all the joints at least 9 times.

I have a feeling i wired up the crossover connections wrongly. I sure hope it is, or else i wouldn't know what else to do. Can anyone take a look and tell me what i'm doing wrongly please? I really appreciate any help i can get. Hopefully i didn't blow up a woofer or something

[sorue]

It suddenly dawned upon me what else could be wrong.. is that wire supposed to be there bridging the woofer + and - ?!

[sdl2112]

It looks like the Madisound diagram is wrong.

It appears the woofer (+) terminal should be connected to the (+W) on the circuit board.



Also just trace it out from Zaph's schematic.

[ThomasW]

It suddenly dawned upon me what else could be wrong.. is that wire supposed to be there bridging the woofer + and - ?!

Nope

[sdl2112]

Nope

From what I can see the jumper should be there. It connects the 12uf capacitor to ground. The wire to the woofer should be moved from this "ground" terminal to the "+W" terminal, a little hard to see but I drew an arrow to show this.

[richnen]

I have had a similar problem with a madisound crossover, I also had no sound coming from the woofers. It turns out that the lead out of the bottom side of the inductor lying flat on the circuit board was shorting across the board. I am sure they would have fixed it under warranty but I am on the west coast and did not want to wait the 2-3 weeks it would take to send it back have them look at it then either repair it or send me a replacement. I ended up carefully prying up the inductor and the bottom lead until I was sure it was only making contact at the point it was supposed to and it solved the problem. I reseated it in silicon, making sure the lead could not make contact with the board except where it was soldered.

If you try to fix it yourself you need to be very careful. My amp has circuit protection that tripped as soon as I turned the system on, before I discovered the problem and solution. Unless you have a way to test the circuits you may cause damage to your amp.

[jkrutke]

It looks like the Madisound diagram is wrong.

It appears the woofer (+) terminal should be connected to the (+W) on the circuit board.

That does appear to be the case and it should work fine when you move the lead. Please let Madisound know about the problem. Their crossover guy may have started wiring the board a different way but forgot to update the schematic. Or maybe it's a simple error, but I know they sell a lot of those ZRT's and I would think the board layout has been standardized.

Regards,
John

[sorue]

Thank you guys for all the help! I shall get to swapping the woofer+ leads.

Most important question - has any damage been done to the woofer by this incorrect orientation?

[BOBinGA]

I don't think you hurt the woofer. You essentially grounded both side of the woofer, so no voltage would be applied across it, therefore, no sound or damage. I don't think you hurt your amp either since grounding the woofer is like not having it in the circuit at all and the coil and cap should provide enough of an impedance so that the amp is not playing into a short circuit.

-Bob

[sorue]

Alright, everything is working now. But the bass is really really anemic, like there's nothing <100 hz.

Could it be because I
1) went with the sealed 20 litre design
2) have too much rockwool stuffing



3) requested madisound to change the L10 inductor from 2.7 mH to 2.0 mH (not sure if they really did)
4) need time for the woofer to break in. Although i don't believe in the usual "necessary" break-in period for most audio gear (especially cables), but there seems to be quite some truth to woofers needing break in. Though I'm not certain the amount of bass will change *that* drastically after breaking in

any thoughts?

[BOBinGA]

1. possibly. A smaller box might help.
2. stuffing's fine
3. reducing the inductor to 2.0 mH will increase the midrange in comparison to the bass.
4. Break in helps some, but not a lot.

Try this. Tape a piece of corrugated cardboard over the hole in the lower shelf brace to make the interior volume smaller. Move the rock wool up a space too. Then listen and see if you hear a difference. If it's still not enough bass for you, move the cardboard up to the upper shelf brace to further reduce the volume and see what it sounds like. If it helps, you can exchange the cardboard for something more permanent. Closed boxes are usually pretty forgiving when the volume is less than theoretically optimum.

-Bob

[fbov]

Alright, everything is working now. But the bass is really really anemic, like there's nothing <100 hz.

1) went with the sealed 20 litre design
2) have too much rockwool stuffing
3) requested madisound to change the L10 inductor from 2.7 mH to 2.0 mH (not sure if they really did)
4) need time for the woofer to break in....

Sealed FR will roll-off below 100Hz, and if you're used to speakers with heavy bass, it may seem nonexistant without EQ. Conversely, sealed has very good woofer excursion control so you have some latitude for EQ, and Zaph measured a 35Hz F10. How does it sound with a little twist of the tone control?

The very low end will benefit from room gain, but the sealed FR is falling too high and too fast to take advantage of it without EQ. However, BSC affects upper bass; which L10 did you get, and how is the bass when the speakers are free standing? Against a wall? In the corner? On the floor in the corner?

Stuffing a sealed box will change the sound, but not kill the bass. Changing box volume as Bob suggests should do the same; subtle changes at best. The pics look fine. Woofers will break in, but I'd be very disappointed if a Scan Speak driver weren't broken in at the factory.

Have fun,
Frank

[Hdale85]

Give it some time before you change anything, bigger drivers take a bit of use to fully break in and generally the bottom end will open up quite a bit.

[cjd]

What are you used to bass-wise? A lot of people seem to prefer a huge bump at 50hz or so. These are nice and flat. Combine with a little more midrange from the inductor change and everything being new and you can quickly add up to "seeminaccurate" when in fact everything is just nice and accurate. So yeah. Give it some time.

[BOBinGA]

One further obvious thing to check is to see if the woofers on both speakers are playing in phase. Even if you plugged them into your amp with positive to positive connections, one of the woofers could be connected backward to the crossover. Double check your wiring. Out of phase woofers have no bass.

BTW, its easy enough to check. Simply reverse the speaker wires on one speaker only. Swap plus and minus on the speaker end of the wire. If you then get significantly more bass, this is the problem.

-Bob

[---k---]

Also room position will matter. Try moving them around a little. And make sure the box is sealed up well.

[owdi]

Verify polarity of the woofers with a battery. A little bit of DC will not hurt them.

BoBinGA - using cardboard to partition off parts of the enclosure is a bad idea as it will flex and move. Better to use a 1/4" - 1/2" thick piece of wood that is screwed down.