Flat frequency response


I am often surprised by the number of speakers with "gee-whiz bang" technology but can't even get speaker design 101 right. I can see the benefit of avoiding a lot of signal processing but preferences notwithstanding, flat frequency response seems like the logical place to start and then progress from there.

1) Why is it so hard to achieve?

2) Does it matter?

3) Is it reasonable to say when you skip the basics you are only progressing on a flawed foundation.

cdc

Speakers exist optimally and really in room which are tuned by one owner for his own ears...Otherwise it is only a well measured abstract design because not living yet in a room and  not yet working for some ears...😊

 

I probably just missed  it, but when you refer to flat frequency response are you referring to the sound level at the listeners position, or say 3 ft from the speaker? If you measure the FR at the listening position, depending on the speaker design, the sound could have rolled off enuf to to ease the FR linearity of a speaker with a flat (+/- 2db) measured a few feet in front of the speaker. FWIW.

Duke is 100% correct. Downward sloping in room which could still be flat/pretty flat at the speaker is perfect. 

@cdc Wrote:

Flat frequency response

JBL engineers speak about flat frequency response in monitor speakers. They believe it should have uniform on and off axis frequency response both horizontally and vertically at all angles. 😎 See article below:

Mike

https://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1981-05%20AES%20Preprint)%20-%20Monitor%20Loudspeaker%20Systems.pdf

 

Really excellent, thought provoking ideas.

audiokinesis

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.

 

Yes. I remember Thiel wanted to keep flat and while some people liked them, I thought too bright. I suppose room and components could come into play.

asctim

It really is difficult to get a speaker to simultaneously have a flat, smooth on-axis response while also having a smooth but downward tilted response off axis at all angles.

Hhmmm, that is a good point.

 

ditusa

They believe it should have uniform on and off axis frequency response both horizontally and vertically at all angles.

Hhmmm, that is a good point too.

 

newbee

when you refer to flat frequency response are you referring to the sound level at the listeners position, or say 3 ft from the speaker?

Haha, good observation. I have been measuring from 3 ft away and also 9 feet away listening. The 3 feet is an attempt a what the speaker really does. 9 feet is the speaker + room. My personal taste is the speakers measures flat through most of the treble so it will have the downward slope at the listening position since the HF rolls off fast.

I’ve had the opportunity to listen to some speakers lately and what I have taken away is the variety in how speakers are voiced. Maybe the designer will voice the speaker to 1) his taste or 2) what he thinks is most popular and will sell the most. It’s a tough balancing act. While the basic sound quality is often excellent, it’s frustrating to hear some frequency variations that don’t suit my taste.

What I see as obviously wrong, and maybe(?) we can all agree on, I made a speaker and was playing with EQ. Depending on EQ, I was shocked to find the singer didn’t even sound like the same person. They both can’t be right.