Balancing Component Frequency Responses


Okay, we won’t sit on the fence with this one. Setting up a system by simply attempting to ‘trade-off’ the frequency responses of the main components is a total nonsense. Hopefully, having come across Vertex, and having read this far into this ‘book’, you will already be getting a feeling that this the case.

Lets say we see a manufacturer’s frequency response graph for a pre-amp which shows a pretty flat response through most of the audio range but we notice it’s output is a little lower through the treble. Now, this graph does serve a purpose; we can see that the pre-amp doesn’t suffer from any significant output level deviations which might be caused by a design error – WHEN MEASURED ON A TEST BENCH. However, to then make the simple assumption that this pre-amp will be good in a system which sounds bright (reducing the brightness of said system by bringing it back into balance), is wrong. Firstly, if the system sounds out of balance, in terms of frequency response, it’s invariably caused by systematic faults and not an aggregate of the individual components’ measured frequency responses. Remember that in particular, intermodulation effects caused by microphony and RFI make a system ‘sound’ like the treble response is up, but it’s not – you are hearing distortion. Also of course, the new pre-amp may or may not suffer itself from systematic faults of its own when it’s used in your system. It may behave microphonically for instance if it’s not on proper supports, so it’s output may sound bright again.

Take care not to confuse detail retrieval with treble response. If a system’s resolving power is down, then it is easy to get this confused with a low treble response. But a lack of resolution is most clearly indicated by a lack of imaging. Remember, good imaging is achieved largely by a system’s ability to reproduce the delicate phase information on a recording. When a system does that well, the perceived treble response is usually excellent too – with high frequencies sounding smooth yet crisp and detailed and not at all harsh or splashy. Applying the Systematic Approach will therefore drastically improve imaging and detail, and by default, remove ‘treble’ problems.

Its a similar story for bass too. Again, trying to find a component that has a ‘better bass’ output, to correct a bass problem is usually not the right place to look first. But we think you have guessed it by now, you have to take the systematic approach – stop the interactive processes that are damaging the bass and it will come back good and strong, rich and vibrant, with pitch and timing to boot.

Certainly be aware of the frequency characteristics of your kit of course, but make sure you do not try and fix system faults with this information alone. It does not work.

Amplifier types – all is not what it seems

Here’s another example of perceived performance being influenced by systematic faults, and not a ‘characteristic’ of the type of device. Over the years, with all the hundreds of different types of systems we have worked with (shows, dealer and customer systems) we have experienced the use of just about every type of amplifier imaginable. From classic valve designs to mega-Watt solid-state monsters. And at the start of each encounter, without any of the Vertex equipment in place, the system of course suffers from all the usual glaring faults – but they are also characterized by the type of amplifier being used (or so we might think at this point in time).

The system based around the valve amp has waffly bass, a reasonable midband, a slightly rolled off treble. It seems better suited to lighter music, struggling with big orchestral stuff and rock music. These traits we lay at the feet of the valves. On the other hand our big solid-state amp seems to give that system a dominating bass, the midband seems sterile and flat, the treble harsh and lacking any delicacy. It seems good at pumping out dance and trance music to organ-rattling levels but lacks any delicacy for a satisfactory rendition of acoustic material (rather sweeping statements we know, but you get the idea). We attribute these traits to the ‘silicon’ solid state power amp.

Now of course other parts of the system will be contributing to these faults too, so let’s assume we now treat the source components (and any other rogue elements of the system) but leave out any treatment around the amplifier. At this stage, the 2 systems will still have the differing traits we discussed. The next stage however tells us something very interesting about the 2 different types of amps, and how they react to systematic faults. As we ‘Vertex’ the amps with kinabalu, roraima, moncayo and then solfonn, the classic characteristics of the 2 amps reduce significantly, to be replaced by a very good all round sound quality.

The valve amp gains grip and control in the bass and the bass now integrates effectively with the midband. The treble gains sparkle and extension. More importantly, the amp seems far less limited to gentle music types – it can groove reasonably effectively now with trance and dance music for instance. The solid-state amp smoothes out and becomes more refined and sweeter, the midband has presence and good tonal form, and the treble sounds natural. Not only does the amp now do a great job with pop and rock, but it can effectively ease-up on the throttle and deliver gentle and elegant music. Choral, baroque and quiet girl-and-guitar stuff can play sweetly at low volume