Flat frequency response

I’ve never envied speaker manufacturers because they have an impossible task of designing a component to work in a room that does not measure flat and will vary greatly in size and overall dimensions.  And, as we all know here, the room has a huge impact on what we ultimately hear.  Yeah, room correction software and/or room treatments can and do help greatly, but still, I’d much rather make cables and take the much higher profit margins and transportability.  God bless speaker manufacturers!

Anyone who wants to hold up "flat" as ideal needs to at least investigate the B&K or the Harman speaker curves. There’s a lot of stuff written there. Also the East Coast vs. West Coast sound. How Klipsch and AR were sounding different from JBL and why.

Also, take a look at the work Floyd Toole has done in terms of determining bass levels vs. user preferences.

Then there’s the issue of hearing and volume. Some speakers really bring out the best at low volumes while others need to be played loud.

This is just the tip of the iceberg when it comes to deciding what a speaker output should be like.

Best,

E

Back when I was an avid amateur speaker builder, I borrowed some test equipment from a technician so I could fine-tune a crossover design, my target being the "holy grail" of flat frequency response. As I got closer and closer to "flat", the sound got worse and worse. Still I persevered, firm in my faith that once I reached "the promised land" of flat measured frequency response, everything would fall into place and the angels would sing.

Well, that didn’t happen. When I finally arrived at "flat" response (plus or minus about .75 dB indicated at the microphone location except for the peaks and dips in the bass region), the sound was harsh and bright and imo unlistenable.

After this highly unsettling experience I started spending as much of my spare time as I could in the library of a nearby university, poring though audio industry journals trying to figure out what had gone wrong and what the solutions might be. Here are the conclusions I eventually arrived at:

1. The in-room response at the listening position dominates perceived tonal balance, and the most natural-sounding in-room response has a gently downward-sloping trend as we go up in frequency (the Harman Curve being an example of this).

2. The spectral discrepancy between the first-arrival sound and the in-room reflection field should be minimized.

3. This means that BOTH the first-arrival sound AND the in-room reflections should have approximately the same gentle downward-slope as we go up in frequency.

Therefore, in my opinion, “getting the basics right” includes getting the first-arrival sound right, and getting the reflection field right.

Duke

speaker manufacturer

@cdc

The book you need to read is Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms by Floyd E. Toole now in its third edition. It will answer a lot of your questions.

I honestly prefer the house curve in my room. This is where the the bass region is above the reference level and trending at a downward slope where the up end of the frequency response(20k) is probably at about 6db/oct. In linear scale, theoretically this will give you a flat response but not in FFT.

One other thing to remember is that having a good frequency response is only the tip of the iceberg. How it sound is another thing.