Man what a pace you guys are keeping in here. Took a while for me to catch up on the last few days postings.
Really sorry to be so late to this topic, it seems that there a lot of strong comments, inputs, considerations, views points and a couple of misunderstandings here.
Let me try to explain this from the TC perspective, please forgive the lengthy post:
When we set out to design these amps, our aim was to create a great performing bass amp range.
Like any other manufacturer we did lots of homework to figure out what was important to bass players and what may not be. Since you are all aware of the APM technology, I won’t bore you with the thought process behind it, but jump to the fact that we designed a technology very inspired by the behaviour of tube-amps, with the many bass player praises of exactly that effect and sound in mind incl. focusing on the perceived loudness of the rig rather than the bench measured spec.
So what does it do? Well, like Tom proved in his detailed BGM review, it, among other things, squeezes the short term top peaks in order to achieve a high average loudness- or power output over time.
As it clearly shows in Toms review, this effect looks very odd when measuring with sine waves, and as Tom pointed out, Bass signals are significantly different from sine waves which we’ve tried to take into account.
Long story short, we ended up with an amp design that is radically different in its nature from most (if not all) other amps out there.
So why did we rate it 450watts then? Well, like Tom, we performed numerous tests and concluded that the performance power of our amp corresponds to that of a 450watt amp, but with a different dynamic span. While a conventional amp shows higher peaks but also deeper valleys, our amp excels in a high average power output over time, by controlling peaks and pulling up the nitty gritty signals as Tom proved in his tests. In our subjective tests, this exact point clearly mattered more to bass players than the short term peaks.
With these findings in mind we felt that a regular RMS power rating would never be able to express how the RH450 performs for bass players, hence we felt that it would be a more correct representation to rate the amp by its bass performance capabilities as opposed to the bench capabilities.
Admittedly, despite our APM document and reference in our material, in hindsight, we probably should have done even more to explain this radically different approach to bass amplification as well as what the 450watts power rating referred to.
I would like to underline that we did read and approve Toms review in detail before it got posted and I compliment BGM for their attention to detail, of course, but even more so, on their ability to bring a multi-facetted view on bass amps to their readers. We did not object to Toms review because it, in large, corresponds with our internal measurements and listening results highlighting the effects of APM both on the bench and not least during practical bass playing.
Finally, a specific detail that I’d like to get out of the way; Even if the RH450 is voiced a bit to the ‘vintage’ side with less of the really heavy subbass and really glassy highs, the voicing of the amp is unrelated to the APM technology.
I hope this helps sheen some light on what our thoughts behind APM and the power rating has been.
Uffe
