What this is for
Soundz is a bench for the audio you already have. Headphones, laptop speakers, a microphone, and a pair of stereo speakers fail in different ways, so they do not share one button. A channel check tells you which side is alive. A tone generator holds a single pitch so a rattle has nowhere to hide. A calculator does arithmetic a speaker cannot hear. Pick the job, then use the control at the top of the page.
Every tone starts quiet and the level slider stops well below full scale. Stop is on the same card as Play. High pitches and low pitches can still be unpleasant, and a subwoofer will move more air than a laptop ever will. If a sound feels sharp, stop it and lower the computer’s own volume before you press Play again. This site will not raise the system volume for you.
How to use the result
The browser can generate a sine, a sweep, and noise with the Web Audio API. It can pan a tone hard left or hard right. It can read a microphone level and play a recording back in the same tab. It cannot certify a frequency-response graph, read a Bluetooth codec, or address rear surround speakers when the output device only reports two channels. Where a number would pretend to be a lab result, the page says it is an estimate or it refuses the number.
Decibels are not one unit. A power ratio uses ten times the log. An amplitude ratio, which is what voltage and most sound-pressure figures are, uses twenty times the log. Doubling amplitude is about six decibels. Doubling power is about three. A decibel figure without its reference — dBV, dBu, dB SPL — is not yet a physical quantity. The calculators keep the reference on the formula line.
What it cannot claim
Microphones stay in the browser. Allowing the mic lets the page draw a meter and, if you ask, keep a short recording as a blob in the tab. Closing the tab drops it. There is no account and no upload. If the browser has already blocked the permission, the address bar is where that changes, not a second button inside the page.
Use headphones for binaural tones and for any left-right judgement you care about. Laptop grilles are often too close together to image, and a soundbar can be a few centimetres wide while the interface still says stereo. Silence at 30 Hz on a laptop is normal. Silence at 440 Hz is not. Start with a mid tone when you are trying to learn whether anything works at all.
Practical notes
Worked path: play Left, then Right, then Both. If the voice and the tone disagree with the cup you are holding, the balance or the cable is swapped. If neither side speaks, change the output device in the system sound panel and try the tone again. If the system’s own test is also silent, stop blaming the browser. If only one side of a pair of headphones is dead at every frequency, that side is the fault, not the sweep.
The pages underneath are the same tools with a narrower job. A bass page does not also try to be a latency estimate. A decibel calculator does not pretend to be a meter. A microphone page does not upload the take. Use the cluster that matches the object in front of you, keep the level modest, and read the limit under the control before you trust a number. If you only have a minute, the channel buttons on this page are the minute.