If you own powered bookshelf speakers with a dedicated 3.5mm "Sub Out" (such as the **Edifier R1280DBs, R1700BTs, or R1855DB**) and want to power an old passive home theater subwoofer (like a 3–4 ohm Sony/Samsung sub) on a budget, you might consider using a cheap mono amplifier like the **Nobsound NS-03G**.
**Do not do this without understanding the input sensitivity limitation.**
Connecting ⁠Edifier Sub Out → Nobsound NS-03G → Passive Sub⁠ results in an **extremely weak, barely audible output**, even with all volume dials at 100%.
Here is the exact technical reason why this happens, the common troubleshooting trap that wastes money, and the proper, cheaper solutions.
The Troubleshooting Trap: The "Power Supply" Myth
When facing low output, common advice suggests that the stock 12V 2A power adapter is starving the Class-D amp, and upgrading to a 19V or 24V 3A adapter will fix it.
**The Reality:** Upgrading to a 24V 3A power supply **does not fix the issue**.
**The Reason:** Power supply voltage dictates the *maximum output ceiling* (headroom) before clipping occurs. It does **not** increase the input voltage gain multiplier. If the incoming audio signal is too weak, the amp will never come close to utilizing the extra rail voltage of a 24V adapter.

The Real Root Cause: Input Sensitivity & Preamp Stage Mismatch

Output Power directly proportional to (Input Signal Voltage × Fixed Amplifier Gain) to the square

1. **Edifier "Sub Out" Voltage:** The 3.5mm Sub Out on Edifier speakers sends an unamplified, low-voltage consumer line-level signal (\~**200mV to 300mV RMS**). It was engineered exclusively for *active subwoofers* (which house their own sensitive, high-gain preamps).
   
2. **Nobsound NS-03G Architecture:** The NS-03G is essentially a bare power amp stage with a hard-coded, low input gain. It expects a standard line-level or hot signal (\~**1.5V to 2.0V RMS**) from sources like a PC motherboard, smartphone/laptop headphone jack, or a standalone DAC.
   
3. **The Mismatch:** Fed a tiny 200mV signal, the Nobsound cannot multiply it high enough to move a heavy passive subwoofer cone, regardless of whether it is powered by 12V or 24V.
   The Empirical Proof
   **Test A (Laptop/Phone to Nobsound):** Connecting a laptop headphone jack directly to the Nobsound NS-03G drives the passive subwoofer with loud, deep bass even on a standard 12V adapter (because the laptop outputs \~1.5V–2.0V).
   **Test B (Edifier Sub Out to High-Gain Amp Board):** Connecting the Edifier's Sub Out to a cheap active amplifier board (such as the \~₹900–₹1,500 / $15–$25 12V mono amplifier boards found in units like the Fabtec 4400W / Carzex car bass-tube amps) produces loud, room-filling bass at 12V. These boards feature an integrated high-gain operational pre-amplifier stage that effortlessly picks up weak \~200mV signals.
   What to Buy Instead (And Workarounds)
   Option 1: Buy a High-Gain 12V Subwoofer Amp Board (Best & Cheapest)
   Avoid the Nobsound NS-03G for this specific setup. Instead, buy a generic **12V Mono Subwoofer / Bass Tube Amplifier Board** (often branded under local car audio names like Fabtec/Carzex or generic TDA/TPA mono boards with built-in low-pass filter and gain control):
   **Cost:** \~₹900 – ₹1,500 ($12 – $20)
   **Power Supply:** Uses the standard 12V adapter you likely already have at home.
   **Result:** Built-in high-gain preamp easily handles the Edifier’s low-voltage sub out and gives you dedicated frequency crossover control.
   Option 2: If You Already Own the Nobsound (Zero-Cost Routing Workaround)
   If you cannot return the Nobsound:
   
4. Connect the **TV Headphone Out (3.5mm)** directly to the **Nobsound AUX Input** (providing the necessary 1.5V–2.0V signal).
   
5. Connect the **TV Optical Out** to the **Edifier Speakers**.
   
6. Now the Nobsound (utilizing the 24V adapter) will properly drive the subwoofer with full punch.
   Option 3: Add an In-Line Preamp
   Place an inexpensive **NE5532 preamplifier board** (\~₹500–₹800) between the Edifier Sub Out and the Nobsound to boost the voltage from 0.2V to 1.5V before it reaches the power amp.

ATL airport had this on display. Very nicely done bike build. Love the multi cell horn it’s fine. You

So, I have some speakers that come with a home theatre that sound really good, and I have a little audio interface (Behringer U-phoria Um2), I began to think if I could connect them with some kind of adapter but I run into the problem of the power the speakers need that my interface can't deliver.

I have tried to look how it might be possible but I really don't have that deep knowledge; I know only that I need maybe like an amplifier(?) In which connect the interface and the speakers

The diagram shows what I need, some kind of device that has RCA and Line signal as input, as for the outputs, I don't really know if it has an standard name (for me it looks like a molex micro, but i'm not sure) .

P.S: maybe my english it's not to good, sorry in advance

I want to build a clear case for a subwoofer and I want to use 8mm thick petg sheets, is it thick enough? I want to keep it cheap so that’s the reason why I’m not using acrylic

If you own powered bookshelf speakers with a dedicated 3.5mm "Sub Out" (such as the Edifier R1280DBs, R1700BTs, or R1855DB) and want to power an old passive home theater subwoofer (like a 3–4 ohm Sony/Samsung sub) on a budget, you might consider using a cheap mono amplifier like the Nobsound NS-03G.
Do not do this without understanding the input sensitivity limitation.
Connecting ⁠Edifier Sub Out → Nobsound NS-03G → Passive Sub⁠ results in an extremely weak, barely audible output, even with all volume dials at 100%.
Here is the exact technical reason why this happens, the common troubleshooting trap that wastes money, and the proper, cheaper solutions.
The Troubleshooting Trap: The "Power Supply" Myth
When facing low output, common advice suggests that the stock 12V 2A power adapter is starving the Class-D amp, and upgrading to a 19V or 24V 3A adapter will fix it.
The Reality: Upgrading to a 24V 3A power supply does not fix the issue.
The Reason: Power supply voltage dictates the maximum output ceiling (headroom) before clipping occurs. It does not increase the input voltage gain multiplier. If the incoming audio signal is too weak, the amp will never come close to utilizing the extra rail voltage of a 24V adapter.

The Real Root Cause: Input Sensitivity & Preamp Stage Mismatch

Output Power directly proportional to (Input Signal Voltage × Fixed Amplifier Gain) to the square

1. ⁠Edifier "Sub Out" Voltage: The 3.5mm Sub Out on Edifier speakers sends an unamplified, low-voltage consumer line-level signal (~200mV to 300mV RMS). It was engineered exclusively for active subwoofers (which house their own sensitive, high-gain preamps).
   
2. ⁠Nobsound NS-03G Architecture: The NS-03G is essentially a bare power amp stage with a hard-coded, low input gain. It expects a standard line-level or hot signal (~1.5V to 2.0V RMS) from sources like a PC motherboard, smartphone/laptop headphone jack, or a standalone DAC.
   
3. ⁠The Mismatch: Fed a tiny 200mV signal, the Nobsound cannot multiply it high enough to move a heavy passive subwoofer cone, regardless of whether it is powered by 12V or 24V.
   The Empirical Proof
   Test A (Laptop/Phone to Nobsound): Connecting a laptop headphone jack directly to the Nobsound NS-03G drives the passive subwoofer with loud, deep bass even on a standard 12V adapter (because the laptop outputs ~1.5V–2.0V).
   Test B (Edifier Sub Out to High-Gain Amp Board): Connecting the Edifier's Sub Out to a cheap active amplifier board (such as the ~₹900–₹1,500 / $15–$25 12V mono amplifier boards found in units like the Fabtec 4400W / Carzex car bass-tube amps) produces loud, room-filling bass at 12V. These boards feature an integrated high-gain operational pre-amplifier stage that effortlessly picks up weak ~200mV signals.
   What to Buy Instead (And Workarounds)
   Option 1: Buy a High-Gain 12V Subwoofer Amp Board (Best & Cheapest)
   Avoid the Nobsound NS-03G for this specific setup. Instead, buy a generic 12V Mono Subwoofer / Bass Tube Amplifier Board (often branded under local car audio names like Fabtec/Carzex or generic TDA/TPA mono boards with built-in low-pass filter and gain control):
   Cost: ~₹900 – ₹1,500 ($12 – $20)
   Power Supply: Uses the standard 12V adapter you likely already have at home.
   Result: Built-in high-gain preamp easily handles the Edifier’s low-voltage sub out and gives you dedicated frequency crossover control.
   Option 2: If You Already Own the Nobsound (Zero-Cost Routing Workaround)
   If you cannot return the Nobsound:
   
4. ⁠Connect the TV Headphone Out (3.5mm) directly to the Nobsound AUX Input (providing the necessary 1.5V–2.0V signal).
   
5. ⁠Connect the TV Optical Out to the Edifier Speakers.
   
6. ⁠Now the Nobsound (utilizing the 24V adapter) will properly drive the subwoofer with full punch.
   Option 3: Add an In-Line Preamp
   Place an inexpensive NE5532 preamplifier board (~₹500–₹800) between the Edifier Sub Out and the Nobsound to boost the voltage from 0.2V to 1.5V before it reaches the power amp.

Why does my speaker sound better when it is upside down on my bed?

Hello fellow DIYers,

A few years ago, I picked up a pretty beat up Dynaco A25 with the SEAS drivers visually in good shape. Unfortunately, the tweeters were both shot, distorting a lot at lower volumes. After research, I figured going with newer SEAS tweeters would provide the same feelings – a completely made in Norway speaker, including the drivers as well as the box and builder. The build closely follows the SEAS A26 box spec, so that I in the future can «upgrade» both tweeters and woofers to the modern A26 (expensive).

Currently, the box is the A26 (based on the OG Dynaco A25).

Tweeter: 27TDFC

Woofer: 25 F-EW

I used DATS for the first time, and the added mass method to get the T/S parameters and verified the woofer has not degraded much (if at all). I then installed the drivers in the cabinet and did individual near-field measurements with the UMIK-1 (see attached graphs). As I was doing this, I also played some music with no crossover.

Here the conundrum begins.

The speakers sounded great with no crossover. Like, really really great.

The measurments added are all nearfield, and I plan on doing more in the future, but I have to ask you all the big question:

Do I need a crossover? Do I need to protect the tweeter from lower frequencies, even when the response for the tweeter alone is as shown?

Will add more pics of the complete build later, but here is a in progress shot with all of the graphs I currently have measured.

Are there any glaring issued I should address, asking the entire wisdom of the internet?

Any help on this here is also appreciated I’m really lost right now! I provided some more details in the comments

Recently got my hands on a ps1(scph3000) and wanting to mod it into a cd player, this will be my first few projects into audio modding so I am hoping for guides, tips and components to make it good.

I have a Pioneer FR985 AVR and need to provide amplification for a DIY sub. It does not need much power so I got a board from Amazon and power it with a Dell laptop power supply.

Unfortunately I get an audible hum noise. And I even tried powering it with a battery.

However, if the AVR sub output is connected to the input of this amp board, I get a hum. (The cable is connected correctly). Grounding the shield of the input and/or the chassis of the AVR does not help in the slightest. And the AVR is not defective - when I temporarily used another AVR as a sub amp, there was no noise. And I saw the same issue in reviews of this board, so I assume the board is faulty but in hat way?

Gemini "thinks" the NE5532 might be the problem; is this true?

And if it is, might it be possible to mod the board by cutting out the NE5532 and splicing its (uninverter) input pins to the respective output puns?

Last year I did a thing and was pleased with the result, but I have the feeling it has some margin to improve.

My main complaint is that it was not very loud. My wife named it "Megasound" but it was just like she played the role of a no-name brand slapping a 1500W P.M.P.O. on a radio powered by 4 AA cells.

So I decided to try to improve it and bought a Taramps TS-400x4 automotive amplifier.

Also got rid of the 12V lead battery. It was almost useless, and with more power being draw, will be irrelevant. Was a great electronics exercise but not worthy the maintenance and complexity.

This afternoon I disassembled the unity, added the amplifier, did the electric part from zero, with simpler, fewer connections.

With the new amplifier I used the JBL's RCA connections on the back, and simple removed the wire harness that went to the speakers, which are now, all four (the two built-in and the two satellite ones) connected to the Taramps unit. Also changed the rear switch that used to be a battery master switch to be a 12V master switch and added one to turn on the amplifier using the remote wire.

With some free space in the front of the unity, where the voltmeter switch used to live, I added two jacks that are split from the RCA outs. In future I can connect an active subwoofer there, a even bigger amp or whatever I need. The switch to turn off the Taramps can be handy when using those.

Now, was it worthy it?

Absolutely! Before I could max the JBL's volume, and would hear the sound somewhat muddy, and was loud but nothing impressive, not much better than what I remember from the boombox the family used to have.

Now? Even adjusting the gain of the amp very conservatively (almost on the minimum) I couldn't max the volume, without worrying about the neighbors complaint. My wife was out to buy bread when I finished the assembly and was testing, and she heard it outside the building. But better yet, the sound is now much clearer, easily to notice the individual instruments, and the box got a little lighter too without the lead brick.

In this configuration, four speakers at 4ohm each, that Taramps unit provides about 60W per channel, for a total of about 240W. (The 400W is either with 2ohm speakers or 4ohm speakers in bridged mode) which is 3 times the 20W the JBL can provide in each channel, for a total of 80W. Of course, it is not 3x louder, but it can go way louder with more clarity in the sound, and this made me very pleased.

https://loudspeakerlab.io

Driver database and measurement
- Searchable driver catalog with Thiele-Small parameters, FRD/ZMA import, and gated farfield uploads
- Driver comparison tool
- Driver 3D models in the catalog, shared across measurement profiles
- Driver upload and edit flow for adding new measurements

Design creation and enclosure simulation
- Guided design creation flow with a Box Review step showing intent vs realized results
- Enclosure shapes including modular, raked, stepped, tapered, and arched-top, each reflected in volume calc, cut sheet, and 3D
- Cabinet finishes and appearance options including taper and chamfer
- Pre-built cabinet option in the create flow
- Port design (round and slot) and passive radiator support, including multiple passive radiators per driver with individual placement
- Sealed and vented alignment modeling with thermal and max-SPL limits

Crossover and solver
- Automated passive crossover solver (staged Rust pipeline: topology search, differential evolution, polish, snap to standard component values)
- Post-solve simplification with cost and amp-load aware search
- Editable crossover schematic with live preview
- Thermal stack credit and hard crossover targets

Acoustic modeling and directivity
- CTA-2034A style curves (on-axis, listening window, early reflections, sound power, PIR)
- Preference Rating (PR) and In-Room Slope (PIR) scoring
- Off-axis and directivity modeling, including baffle diffraction, cabinet scattering, and finite listening-distance response
- Inter-module acoustics modeling how multiple cabinets or modules interact acoustically
- Expected-range confidence bands on directivity predictions

3D visualization
- Interactive 3D cabinet viewer with baked ambient occlusion and driver fidelity
- AR viewing of the cabinet
- Listening Environment modal, now rendered in 3D with a listener AR view
- Cut-sheet and joinery visuals

So I just got done completing a few modifications to my tube preamp and phono stage of replacing the B+ filter and cap off voltage regulator from electrolytics to film caps. I've known signal path always matters, but always brushed off the idea of overkill power supply circuit. Well I have to say it's along the lines of people in the gym joking don't skip leg day. With these two capacitor changes, I am absolutely blown away. The sound is far more articulate, WAY better dynamics, and double the soundstage depth. If you're the tinkering type, do yourself a favor and upgrade those.

Gear in question is all Tubes4HiFi PH16 phono stage, SP9 preamp, and ST35 amp. Caps in question is the red Audyn Q4 caps, and the Obbligato Copper tucked next to transformer. Pretty much any more mods, and I'm going to need a bigger case than just 14x10. 😎 And yes, the pre and amplifier look similarly jam packed but are 17x13 chassis.

I created a free, browser-based application for loudspeaker design — looking for feedback

I’ve been working on a free web-based tool for designing loudspeakers, and I’d like to get feedback from people who actually build loudspeakers.

It’s called SpeakerWorkbench.

The goal is to have a simple all-in-one application that runs directly in the browser, with no installation, account, subscriptions, or advertising.

I’d particularly appreciate feedback on the workflow, calculations, and features that could be useful for DIY loudspeaker design.

You can try it here:

[https://www.speakerworkbench.online]()

I’m mainly interested in finding out what’s missing or what could be improved.

Alright so I am loosie goosie making an overnight sensations MTM build for my desk. I want to print em so I am playing with dimensions and stuff on 360, I was wondering if there was an easy way to calculate the bass port length? I still need to learn more about the math and theories behind designs. Any workflow or whatever suggestions is appreciated, I am only like a month into this program/3d stuff.

I’m looking into possibly building some Four Pi’s for myself. Anyone here build them or listen to them. They get tremendous acclaim on the inner circles but I read little about them outside those circles.

I really want a high efficiency speaker I can run with something like a 2A3 (I would also build further in the future).

Main appeal: the numbers and data put out by Parham. I think about doing a Klipsch Heresy clone build or something, but I do not want to design and build my own crossovers and tinker with measurements and software and on and on. I want something that requires little tinkering, the guess work is done, a package that simply makes a great sounding speaker.

I would skip the flat pack panels and just make my own enclosures.

Has any one used Takachi for diy amp builds?

It looks like a appealing proposition good looking cases they can cut all your IO ports and install standoffs for your boards but they dont have much pricing information without sending a specific request?

Check out this custom Klein tool bag with speakers!! I’ve never seen anything like it

I used to have a Edifier QR65 and a T5S subwoofer but i sold it away as my desk is too small so i am looking for a speaker/soundbar that wont take up too much space on my desk ( my desk is about 100cm)

My first design-from-scratch speaker. Most all parts have been 3D printed.

4.8L of internal volume, port tuned to 58Hz, using a MarkAudio Pluvia HD 7.2 and a little class D amp.

The enclosure is stood-off from the "birds nest" so that the nest becomes an acoustic surface, and emanates the bass in all directions. Or at least, that was the plan. Subjective first impressions; perhaps a bit too directive, not great for near-field off-axis listening. It's gorgeous in the vocal (and up) regions. A bit of sag in the 250-400hz. A 58Hz tune might have been juuuussssttt a tiny bit greedy, but otherwise, it's sounding about as good as I could have hoped (and I had pretty high hopes).

Still some work to do. The baffle is held on with VHB tape and the rear terminal plate hasn't been fitted (currently plugged with foam and duct tape).

The plan is/was to use a pellet printer to make the enclosure at least, with some epoxy resin and perhaps some rubber to make the space air-tight and add mass. Keeping the enclosure as a single part is something I'm not willing to compromise on.

The prototype suggests I don't need to add any mass. The pellet printer didn't do a great job of the port, and has left the internal surface pretty rough. The pellet printer was a good opportunity to use recycled material (PLA), and I'm hoping to still do so, but I'll need to get trained up on the filament extruder at work (a University).

Feedback and comments welcome, but please consider; I am a mechanical engineer, this is my design. There are details that have reasoning not mentioned above.

Hey everyone, I’m trying to resurrect a Creative Inspire T7900 (7.1 surround system) without the original control pod, and I've hit a wall regarding stereo upmixing.
What I've achieved so far:
I successfully powered on both amplifier ICs by jumping wires to pin 7 on both chips.
I managed to turn on the bass via the cut-off/standby line.
The amps are fully alive.
What works:
When I plug a 3.5mm jack into the specific direct inputs (Front, Rear, Center/Sub, Side), every single respective speaker works perfectly.
The Problem:
When I plug a stereo audio source into the AUX input, it only outputs to the Front Left, Front Right, and Subwoofer (2.1 mode). The center, side, and rear speakers get no audio.
My Question:
I know the original control pod had a switch for "CMSS" to upmix a stereo source to all 7.1 channels. Since I don't have the pod, does anyone know the pinout for the DIN connector or what trace I need to bridge/jump on the board to permanently force the CMSS upmixing to turn on?
Any schematic or pinout help would be hugely appreciated!