1. You’ll agree that it’s essential that your amplifier or amplifiers being auditioned should be as close to tonally consistent across the spl (volume) band as possible i.e. no bass, or mid or treble emphasis (or dropout) as the volume is changed.
2. That the only fair comparison between any two components (amps in this instance, but it could be anything else really) is that they are compared at your choice of an identical spl.
Okay – so far so good. Here’s the problem. Very, very few retailers offer this. Probably because it’s never occurred to them – or nobody asked, or they think it’s irrelevant, inconvenient or whatever. So the answer is that before the demo starts, you politely but both calmly and firmly insist that it does.
Quite the reverse!
It’s no good the sales advisor setting by ear the volume between one amp and the other. It’s not that the human ear is insensitive. Far from it. The problem is quite the reverse. The human ear can detect very small changes in decibel levels. The difficulty is that very rarely can it accurately recall the db output of amp ‘A’ when setting it for amp ‘B’. Thus an unintentional slight variation on the two settings can exert a very significant impact on your decision and your wallet!
Close enough just isn’t good enough.
You should go armed with a simple, inexpensive sound pressure meter. You can’t rely on the retailer to have one. A digital read-out one is the most useful.
Examples can be seen HERE from around £16.00. You don’t need anything flash. No tricks, no gimmicks and no tools that you’ll probably never use. All you want is a fast, accurate and uncomplicated method of determining the spl volume from your seated position.
You also need a source of white noise. If you are unfamiliar with this term then you can read about it HERE. It’s available on vinyl record and cd. As a substitute (reasonable but not ideal) you can use the between station hiss on a FM tuner / radio.
Considering how much you have to loose …
The investment is tiny – compared to the consequences of buying an item not on 28-day sale or return. Just stop to consider this.
It really isn’t sensible to insist that the sales advisor use these two tools. Politeness is the approach here. Invite them to participate.
Here are the stages:
- You play music. Anything will do. The objective is to set your preferred spl listening volume – for BOTH amplifiers. Start with amplifier ‘A’ – say for example 90db as registered on your sound pressure meter
- Then you select either the vinyl white noise or the cd version through amplifier ‘A’ – without adjust the volume setting.
- Amplifier ‘B’ is substituted and the white noise is played and the volume control adjusted till it precisely and I do mean precisely matches that of ‘A’ as registered on the sound pressure meter.
- Both of you note down the marking on the volume control of both amps.
- The demonstration starts as is usual – except that now you are making a far more accurate comparison than is the norm.