槽腹板比
| 槽腹板比 | = | 前腹板长度 |
| 后腹板长度 |
对于成形条形变幅杆，为获得合理的前腹板应力，前腹板长度在 20 kHz 时一般约为 12 mm，而槽腹板比约为变幅杆增益的倒数。这使得后腹板比前腹板更长，从而得到相对较短的槽，既能最大限度减少相邻非轴向谐振带来的问题，又能保持合理的后腹板应力。
Slot web ratio
| Slot web ratio | = | Front web length |
| Rear web length |
For shaped bar horns, the front web length is generally about 12 mm at 20 kHz for reasonable front web stress and the slot web ratio is approximately the inverse of the horn gain. This results in a rear web that is longer than the front web, thereby yielding a relatively short slot that minimizes problems with adjacent nonaxial resonances while still giving reasonable rear web stress.