Do we have a head transfer function? Do on-line reviews matter?

[Hari Iyer]

This post is based purely on my own objective measurements and subjective listening and others may choose to differ.

Past 6 months i have been living with my previous OB speaker and my new ones which was built 3 months ago. The first order crossover for this speaker was completed around 2 weeks ago. I both listened and measured these speakers couple of times to understand what is going on with them.

When i measured the speaker as per standard norm, they sound reasonably flat from 40Hz till 20KHz with excellent step and other measurements. But when i listen to this speaker if will always find them little thin in subbass and somewhat brighter highs. So past 10 days i tried to fine tune them by listening without much regard to how they measure. I later measured them as to how the settings measured. I noticed that i prefer an increased bass in the subbass region below 100Hz by around +3db. My head prefers a flat response from around 100Hz till around 7KHz and from there on a slowly rolling off response from 7KHz till 20KHz so that the 20KHZ is around -3db to -6dB down. This measurement allows me extended hours of listening pleasure without fatigue and to my liking.

The fundamental question is this - Do we all have an head transfer function (TF)? How many variables do we consider before our head transfer function? I can think of the following transfer function - source TF, Amplifier TF, Speaker TF, Room TF. Not to mention TF of power cables, IC cables and Speaker cables. I am not even considering what happens in the recording studio before the source - the venue, the hardware, the head TF of the recording engineers etc. This is a topic for another post.

If there are going to be so many variables for your dream Nirvana sound then how does it matter to alter just one of the TF and expect a whole lot of difference. This makes the effort quite challenging especially if you do not know which TF is causing the bad/ offending sound. Consider yourself luck if only by changing the cable TF and room TF(proper placement) you are able to achieve to match all the previous TF from source TF to room TF to match to your head TF.

In this context the DIY setup looks promising to me as you can experiment to some extent what is your own preference of cable TF, speaker and Amplifier TF without huge damage to your pocket.

So comes my next question - does online review of equipment, cables, speakers etc. does even make sense by a reviewer as we have a major Head TF of the reviewer coming into place which will be completely different from your own Head TF. So i take such reviews with a pinch of salt (no offence intended) because of the very fact that the Head TF is simply not the same. Let alone other TF like room, cables etc. I would like FMs to pen down their opinion about how they found a particular amplifier / speaker combination to sound very nice in one venue but when the bought the same set of amplifier/ speaker at their home the magic was not there because the source, cable, room TF were all completely different.

Thanks for looking.

 

[Vineethkumar01]

The phenomenon at work regarding preferred sound balancing sounds familiar


However the above is just a small part of the overall picture about why one prefers such a sound balance.
Part of it all comes down to personal preferences.
Another part of it comes down to speaker design and acoustical sound power matching across the full spectrum based on different radiator types used in the speaker. Specifically in your case with at least low & mid-frequency (constant directivity) dipole radiation, it is theoretically possible that the total acoustic power radiated in the woofer range is about 3dB less than the total acoustic power radiated in the mids. See here for a deeper discussion about the matter:

Power matching

Then comes the constant directivity horn at the top (I assume there is no dipole radiation in that range with this speaker). With a constant directivity horn, most people prefer a down-tilted sound balance in-room.
The situation might have been different if that region too had dipole radiation.

Regarding audio reviews etc, etc, may God help us all.....

 

[Hari Iyer]

I could completely relate to what is written here. If I place my speakers parallel to my room walls the situation becomes wore and then for getting proper center image I too have to sit in-between the speakers.

When I consider the diagonal speaker placement then the center image is everywhere and I can sit anywhere in the room and still get the exact imaging. I had to biamp my speaker system to achieve the low- mid balance which was difficult with going all solo. Currently my h- frame and diople midrange are on the same axis and I can feel the increased bass on the speakers even if I try to lower the woofer level. As suggested I shall try the 45 deg angle trick on the H- frame with the same on- axis position for the dipole midrange and see if there is a balance in the acoustic power response.of the two independent dioples.

The HF driver anyway is a monopole and probably radiates in a constant directivity mode due to the circular waveguide used. This is also time aligned with the diople midrange to have a meaningful polar response.