Formula Used
Side distance: Room width × side wall ratio. The common Cardas value is 0.276.
Front distance: Room width × front wall ratio. The common Cardas value is 0.447.
Speaker spacing: Room width − 2 × side distance.
Speaker to listener distance: Speaker spacing × listening triangle ratio.
Listener depth: Front distance + square root of speaker-to-listener distance squared minus half speaker spacing squared.
Toe-in angle: arctangent of half speaker spacing divided by triangle depth.
Axial mode: Speed of sound ÷ 2 ÷ room dimension.
Example Data Table
| Room |
Length |
Width |
Height |
Side Distance |
Front Distance |
Speaker Spacing |
| Compact room |
16 ft |
10 ft |
8 ft |
2.760 ft |
4.470 ft |
4.480 ft |
| Medium room |
20 ft |
12 ft |
8 ft |
3.312 ft |
5.364 ft |
5.376 ft |
| Large room |
26 ft |
16 ft |
9 ft |
4.416 ft |
7.152 ft |
7.168 ft |
How To Use This Calculator
- Measure the finished inside room length, width, and height.
- Select feet or meters before entering all values.
- Keep the default Cardas ratios, or enter your own ratios.
- Add speaker cabinet depth to check rear cabinet clearance.
- Enter the minimum rear clearance wanted behind the listener.
- Press the calculate button.
- Mark the speaker and chair positions on the floor.
- Export the result for installers, contractors, or project records.
Why Cardas Setup Helps
A Cardas room setup uses ratios linked to the golden section. The goal is simple. It moves speakers away from strong boundary pressure zones. It also keeps left and right placement balanced. This calculator turns room dimensions into clear marks. Builders, designers, and audio owners can use the marks before furniture is fixed.
Planning The Room
Start with the clear inside width. Measure between finished side walls. Then measure length from the speaker wall to the rear wall. Height helps you judge volume and modal risk. The calculator uses width as the main reference. It places each speaker center 0.276 of the room width from the nearest side wall. It places the speaker baffle 0.447 of the room width from the front wall. These values create a balanced triangle without guessing.
Reading The Results
The result panel gives side distance, front distance, speaker spacing, listener position, rear clearance, floor area, and room volume. It also estimates a toe in angle. Use that angle as a starting point only. Real speakers vary. Some need less toe in. Others image better when aimed near the listener. Always mark the first layout with tape. Then test small movements.
Construction Notes
Room setup is easier before final trim, built ins, and cable paths. Leave enough wall space for acoustic panels. Keep large cabinets away from first reflection points. Avoid placing the listening chair against the rear wall. The rear clearance warning helps here. If the chair is too close, try a shorter listening triangle. You can also rotate the room when width and length allow it.
Practical Use
Cardas ratios do not replace measurement. They give a strong first layout. After setup, play familiar speech and simple music. Check center image, bass smoothness, and depth. Move speakers in small equal steps. Keep notes after each change. Use the CSV and PDF options to save the starting plan. That record helps contractors, installers, and owners discuss the same layout clearly.
Final Adjustment
Treat every result as a measured baseline. Use identical tape marks for both speakers. Confirm distances from the front wall and side walls. Recheck chair height and ear location. Small rooms may need more absorption behind the listener later.
FAQs
What is a Cardas room setup calculator?
It estimates speaker and listener placement using Cardas-style room ratios. It gives side distance, front distance, speaker spacing, toe-in angle, and rear clearance from your room dimensions.
Which room width should I enter?
Enter the finished inside width between the two side walls. Do not include wall thickness, trim depth, or unfinished construction measurements.
Can I change the Cardas ratios?
Yes. The default ratios are editable. Keep 0.276 for side placement and 0.447 for front placement when you want the standard starting layout.
Does this replace acoustic testing?
No. It gives a reliable starting point. Final placement should be checked with listening tests, room measurements, and small equal speaker movements.
Why is rear clearance important?
A listener too close to the rear wall may hear strong bass peaks and reflections. More clearance usually helps imaging and smoother low frequency response.
What does toe-in angle mean?
Toe-in angle means how much each speaker turns toward the listener. Use the result as a starting angle, then adjust for imaging and tonal balance.
Can I use meters instead of feet?
Yes. Choose meters from the unit field. The distance formulas stay the same, while axial mode estimates use the metric speed of sound.
Why add speaker cabinet depth?
Cabinet depth helps check whether the rear of the speaker has enough clearance from the front wall after setting the front baffle position.