This page does not review anything Grado makes. It counts one thing: how much of what this database says about their products came out of their own documents, and how much had to be worked out or left blank.
| Model | Impedance | Sensitivity | Source of the figure |
|---|---|---|---|
| GS1000 (Classic) | 38 Ω | 99.8 dB/mW | Published per mW |
| GS3000x | 38 Ω | 99.8 dB/mW | Published per mW |
| GT220 | 32 Ω | 100.0 dB | Not published |
| PS2000e | 32 Ω | 99.0 dB | Not published |
| RS1x | 38 Ω | 99.8 dB/mW | Published per mW |
| RS2x | 38 Ω | 99.8 dB/mW | Published per mW |
| Signature HP100 SE | 38 Ω | 117.0 dB/mW | Published per mW |
| Signature S550 | 38 Ω | 112.0 dB/mW | Published per mW |
| Signature S750 | 38 Ω | 115.0 dB/mW | Published per mW |
| Signature S950 | 38 Ω | 117.0 dB/mW | Published per mW |
| SR125x | 38 Ω | 98.0 dB/mW | Published per mW |
| SR225x | 38 Ω | 98.0 dB/mW | Published per mW |
| SR325x | 38 Ω | 98.0 dB/mW | Published per mW |
| SR60x | 38 Ω | 98.0 dB/mW | Published per mW |
| SR80x | 38 Ω | 98.0 dB/mW | Published per mW |
Impedance is almost always printed. Sensitivity is the one that goes wrong, because a decibel figure means two very different things depending on whether it is per milliwatt or per volt — about five decibels apart at 300 Ω and eighteen at 16 Ω. The conversion is here.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| GS1000 (Classic) | 8-35 | not printed | not printed |
| GS3000x | 4 - 51,000 hz | not printed | not printed |
| GT220 | nothing printed | — | — |
| RS1x | 12-30,000 hz | not printed | not printed |
| RS2x | 14-28,000 hz | not printed | not printed |
| Signature HP100 SE | 3.5 Hz – 51.5 kHz | not printed | not printed |
| Signature S550 | 6Hz - 44kHz | not printed | not printed |
| Signature S750 | 4Hz – 48kHz | not printed | not printed |
| Signature S950 | 3.5 Hz – 51.5 kHz | not printed | not printed |
| SR125x | 20-20kHz | not printed | not printed |
| SR225x | 20-22kHz | not printed | not printed |
| SR325x | 18-24kHz | not printed | not printed |
| SR60x | 20-20kHz | not printed | not printed |
| SR80x | 20-20kHz | not printed | not printed |
Grado prints a frequency range for 13 of all 14 models here whose sheets have been read, and nothing for the other 1.
Not one of those ranges comes with a tolerance in decibels. Without a ±dB figure a range says nothing about how loud the headphone is at either end of it, which puts Grado with the majority: of the 490 models across this database whose maker prints a range, 58 print the tolerance.
Every range stands under the same heading: “Frequency Response”.
1 further model of theirs in this database has no page left on their site at all, so there is nothing to read for it either way. That is counted separately from printing nothing, because it is a different fact.
No measurement is published here — only what was printed. The whole count, maker by maker, is in the frequency response audit.
The hardest of the 15 to drive is the Grado SR60x: 1.6 mW and 0.25 V for a 100 dB SPL peak. Their impedances run from 32 to 38 Ω, which matters because the voltage a headphone wants rises with impedance while the power falls.
280 of the 280 sources here reach 100 dB on all 15, and the cheapest of them is the Apple USB-C dongle (EU) at $9. “Reaches” means the maker’s own published power figure is enough at that load; it is not a judgement of how it sounds.
On hiss the count is smaller, because most of the industry does not publish a noise figure at all: of the 83 sources here that do, 82 stay under the threshold of hearing on it. The one to watch is the Grado GT220 at 115 dB/V — the more sensitive the in-ear, the more of the amplifier’s own noise you hear.
Their lowest impedance is the Grado PS2000e at 32 Ω, so a source wants an output impedance at or below 4.0 Ω to satisfy the one-eighth rule on everything they make. 134 of the 169 sources that publish an output impedance manage that.
These counts use figures the source makers published themselves. A product that publishes nothing is not counted as a pass anywhere above, which is why the three numbers differ so much. The collection matcher runs the same arithmetic over whatever you actually own.
Most of what this site says about Grado came from them, with the rest derived and labelled as derived.
The rule used here is the same for every maker and is described on the manufacturer index. Every figure behind it can be opened on the product page it came from, with the document it came from linked.