SDA 2.3 No bass

Gardenstater · July 10

Black Terminal and Red Terminal are referring to the binding posts. Black is negative and is the one on the right, and Red is positive and the one on the left. Have you looked at the schematic. Even if you are a novice at schematic reading it might be of some help.

JCL · July 10

I would take the measurements from the back of the speaker at the binding posts and the SDA connection. That’s where I took them and I believe that’s where they were intended to be checked.

tragusa3 · July 10

Measured at the binding posts, everything measures spot on.

George, the schematic is a foreign language to me, but I'm trying.

Gardenstater · July 10

tragusa3 wrote: »

Measured at the binding posts, everything measures spot on.

George, the schematic is a foreign language to me, but I'm trying.

Now, what do you get for R5 when you have first disconnected the sub-bass donut drivers? Is it the same? Just curious if those drivers are not getting proper current due to bad connections or an open circuit sub-bass inductor, etc..

tragusa3 · July 10

With both donuts disconnected, R5 (black to red at the terminal) changed from 4.1ohm to 3.8ohm

Seems minimal?

Gardenstater · July 10

tragusa3 wrote: »

With both donuts disconnected, R5 (black to red at the terminal) changed from 4.1ohm to 3.8ohm

Seems minimal?

It is. May or may not be normal. If there were no change whatsoever that would've meant there is an open circuit on the supply or return side through the sub-bass inductors. When you said they are moving maybe 50% I thought there could be a possibility it was entirely due to back wave energizing them. 20dB down from flat at 40Hz is huge and can't be entirely due to some room acoustic anomaly. I don't know where you measured though; what distance from the speakers etc..

Next step would be to remove that faston on the white wire where it connects to the sub-bass inductor and clean it (the male side) with something like some 0000 steel wool or maybe 1500 or finer grit sandpaper or DeOxit if you have some (on male and female). Make sure the connection is tight and if not crimp the female faston slightly tighter. Then see what it measures when everything re-connected. See if the 4.1 ohms changes and listen. Basically you just want to clean all connections and make sure they are tight, with all the midwoofers circuits but especially the sub-bass and stereo ones.

I would also proceed with making sure the cabinet is sealed up as tightly as it should be.

PS: Have you made certain that your red binding post nuts (+) are on the left on both speakers? If they were swapped on one of them, and you were wiring your amplifier to them according to color only, you could get huge bass cancellation effect.

F1nut · July 10

Wow, just wow

skipshot12 · July 10

If it’s not a really good sealed cabinet you wouldn’t get the tightness in the bass region, bass would sound boomy. But, the bass will still be there.
Something else is going on.

Grab a schematic and trace all connections to be wired correctly along with continuity.Yes it’s a pain in the **** but you need to start eliminating what isn’t wrong.

There’s no way slight air leaks would cause a 30db drop in bass…

Tony M · July 10

How about the speaker wire polarity hooked up to the amp?

I know it sounds unlikely but I've made the mistake once or twice in my old age.

skipshot12 · July 10

Don’t get frustrated.
Take your time.
You’ll learn as you go…..

A lot of knowledge on this forum. These folks have been there done that.
There are no stupid questions.

F1nut · July 10

skipshot12 wrote: »

If it’s not a really good sealed cabinet you wouldn’t get the tightness in the bass region, bass would sound boomy. But, the bass will still be there.
Something else is going on.

Grab a schematic and trace all connections to be wired correctly along with continuity.Yes it’s a pain in the **** but you need to start eliminating what isn’t wrong.

There’s no way slight air leaks would cause a 30db drop in bass…

The air pressure from mid-drivers drive the PR, so if there is an air leak like the OP has there will be no bass, boomy or otherwise.

tragusa3 · July 10

George, thanks. I will get to cleaning all fastons.

F1, I have yet to put the adhesive inside the cabinets. I have tightened the nuts. I've looked very closely at all surrounds and found two small locations where I added some glue. You may be right about airleaks causing it, but it's hard to sell me on that with such a HUGE discrepancy.

Tony, thanks. I just checked again. Yes, I've done it before...

Skipshot12, thanks for the encouragement. I'm keeping faith. I am not afraid to ask questions. My wife says that I'm humble to a fault when it comes to knowledge. She claims I'm an expert at most things.

Gardenstater · July 10

Are the Red binding post nuts on the left side for both speakers?

tragusa3 · July 10

Sorry, meant to respond to that. Yes they are and I've verified the wiring from the crossover to the binding posts.

Gardenstater · July 10

tragusa3 wrote: »

Sorry, meant to respond to that. Yes they are and I've verified the wiring from the crossover to the binding posts.

Okay. Well I was hoping for your sake that it was that simple 🤣

SCompRacer · July 10

What are the dimensions and type of room they are in? The reason I ask, if you cannot find anything terribly wrong with the speakers, the room could be a contributing factor.

Once upon a time I experienced a room at a friend's house where a better pair of speakers capable of deeper bass than the ones they replaced actually had less bass than the ones they replaced. Leaving the room, the best bass was found outside the door to the room in the hallway. I found it hard to believe but I had experienced it.

michaeljhsda2 · July 10

I don't see where this has been mentioned but are the jumper wires to the upper and lower binding posts in place?

skipshot12 · July 10

F1nut wrote: »

skipshot12 wrote: »

If it’s not a really good sealed cabinet you wouldn’t get the tightness in the bass region, bass would sound boomy. But, the bass will still be there.
Something else is going on.

Grab a schematic and trace all connections to be wired correctly along with continuity.Yes it’s a pain in the **** but you need to start eliminating what isn’t wrong.

There’s no way slight air leaks would cause a 30db drop in bass…

The air pressure from mid-drivers drive the PR, so if there is an air leak like the OP has there will be no bass, boomy or otherwise.

^ Respectively disagree with this.

Not an SDA expert here by no means but, playing my SDA SRS’s for the first time they had plenty of low end bass…. Before starting on my mods.
End caps were so loose I took them off with my fingers, as were all the drivers along with the passive.
Bass was still there.

There’s something else causing the 30 decibel drop.

tragusa3 · July 10

Hey Michael, welcome to the show. Jumpers are in, good catch.

Scompracer, welcome. The room I'm currently in is too small for them (14'x12'). I've placed them in a dozen spots and walked the entire first floor of the house to see if the bass was anywhere. I'm quite familiar with integrating subs in a room, as I have a theater with multiple subs that I have spent years dialing in with placement, REW and a parametric eq. There is something in this cabinet that is cutting me off at the knees. When I bought my SDA1C's, I had a similar issue and DID find a polarity issue on some drivers. Hasn't been that easy this time. I'm not saying bass is weak or thin...it is not being produced.

Clipdat · July 10

As a side note, welcome to the forum. Hopefully after you get this mystery solved you'll stick around and talk music and gear with us.

tragusa3 · July 10

Is there a way to measure voltage making it to each driver? Would that tell me if the driver is getting what it should? If I played a test tone and measured voltage at every driver? I wouldn't know what the voltage is supposed to be, but I would see if something was a standout anomaly. Helpful?

I'm glueing interior seams in the cabinet right now and while drivers are out, glueing the magnets too.

I have to do something to feel productive.

gmcman · July 10

tragusa3 wrote: »

construction adhesive on the inside seams.

Someone can correct me if I'm wrong, but I would use a sealant and not construction adhesive. If you need to remove/replaced the end caps in the future, the construction adhesive could damage the cabinets upon removal.

gmcman · July 10

What are you driving the speakers with, an AVR maybe? Just something to check, if using an AVR, make sure you don't have speakers set to small or have the sub selected and a cutoff at maybe 80HZ.

Clipdat · July 10

Great suggestion!

tragusa3 · July 10

gmcman wrote: »

tragusa3 wrote: »

construction adhesive on the inside seams.

Someone can correct me if I'm wrong, but I would use a sealant and not construction adhesive. If you need to remove/replaced the end caps in the future, the construction adhesive could damage the cabinets upon removal.

It's on there now! I don't think I put it anywhere that I would ever take apart?

tragusa3 · July 10

gmcman wrote: »

What are you driving the speakers with, an AVR maybe? Just something to check, if using an AVR, make sure you don't have speakers set to small or have the sub selected and a cutoff at maybe 80HZ.

Ya'll are good at catching the obvious little things. For once, I've addressed most of them. They are connected to an Emotiva XPA amp putting bwtween 4-500 watts per channel to them. No processor. Bluetooth dongle directly to amp. In the last month, I've had 6 +/- other speakers connected to this and they all sounded great. Thanks.

tragusa3 · July 10

Clipdat wrote: »

As a side note, welcome to the forum. Hopefully after you get this mystery solved you'll stick around and talk music and gear with us.

Thanks brother! I like a little bit of troubleshooting, but I do enjoy the music more!

Clipdat · July 10

Bluetooth dongle?

Well, assuming no software EQ in play on your phone/app then I guess it's not that.

tragusa3 · July 10

For your viewing pleasure.

Clipdat · July 10

My uneducated **** says it's something wrong with the crossover.

SDA 2.3 No bass

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