What Is Frequency Response? || Understanding the Measurements Part 1

Summary

このビデオスクリプトでは、オーディオレビューのデータ意味を解説するシリーズの第1回として、周波数応答について詳しく説明しています。オーディオレビューでは、主観的な意見だけでなく、客観的なデータを提供し、リスナーが自分の好みに合った音質を選ぶ手助けをします。スピーカーの周波数応答は、リスナーが最初に耳に入る音を表すため、非常に重要です。理想的には、スピーカーは再生システムから出る信号をそのまま再生すべきですが、完璧なスピーカーは存在しません。スクリプトでは、周波数応答グラフの読み方や、±1.5dB以内が良好、±3dB以内が普通とされていますが、それ以上になると音の色味に影響を与えます。また、スピーカーの種類にかかわらず、低音域を補強するサブウーファーの重要性も触れています。

Takeaways

• 🎶 オーディオレビューの目的は、データを提供することで、個人的な主観的な意見に頼らないようにする。
• 📈 主観的なフィードバックと客観的なデータの両方を提供することで、聴く人々が異なる可能性のある聴覚体験をカバーする。
• 📊 オブジェクトデータは、オーディオレビューアーがただ「ミドルレンジが温かそうだ」や「ツイーターが詳細だ」と言わないようにするために重要。
• 📚 このシリーズのビデオは、データを理解するための教育的な目的で、観客がデータの意味を理解できるように説明する。
• 🔊 オンアクシス周波数応答は、スピーカーの性能を理解する上で最も重要な客観データの1つである。
• 🏠 アネコイック測定と測定された部屋内の応答は異なる。アネコイック測定は、部屋の影響を排除してスピーカー自体の性能を測定。
• 📉 周波数応答グラフのx軸は周波数で、y軸はSPL（Sound Pressure Level）で、これは音量の大きさを示す。
• 🔉 理想的なスピーカーは、再生システムから出る信号を変更せず、同じ忠実性を維持する。
• 📌 スピーカーの周波数応答が±1.5dB以内であれば良いスピーカーであり、±3dB以内であれば十分に良いが、それ以上になると問題が生じる可能性がある。
• 🚫 スピーカーが20Hzから20kHzまでの平坦な応答を提供することは困難であり、完璧なスピーカーは存在しない。
• 👂 高域周波数の異常が聞こえる可能性があり、それが聴覚に与える影響については、レビューで詳しく説明する。
• 🔗 説明書に記載されているすべての測定方法は、ANSI/CTA-2034-Aという標準に基づいており、無料でダウンロードできる。

Q & A

アロンスのオーディオコーナーというシリーズのビデオの目的は何ですか？

アロンスのオーディオコーナーは、視聴者にデータを提供することで、主観的な意見に頼らずに製品を理解できるようにすることを目的としています。

アロンスはどのようにしてスピーカーをテストしますか？

アロンスは、リビングルーム、ホームシアタールーム、近場、遠場など、様々な状況でスピーカーをテストし、異なるリスナーが聴く可能性がある様々な状況を網羅しようとしています。

主観的なフィードバックの問題は何ですか？

主観的なフィードバックの問題は、私が聞こえるものがあなたに聞こえるとは限らないことです。私たちは異なる要素に注意を払っているかもしれませんし、低い周波数や高い周波数の聴覚損失があるかもしれません。

オブジェクトデータとは何ですか？

オブジェクトデータとは、スピーカーの性能を客観的に示すデータであり、時間とともに提供されるデータが増えることで、リスナーは自分の好む音質や参照音を絞り込むことができます。

アロンスが提供するデータの基準は何ですか？

アロンスが提供するデータは、ANSI/CTA-2034-Aという標準に基づいています。これは家庭用スピーカーのための測定方法の標準的な方法です。

オニキス応答とは何ですか？

オニキス応答とは、部屋の影響を受けずに行われる測定であり、スピーカーが独自に何をしているかを知るためのものです。

周波数応答グラフのx軸とy軸は何を表しますか？

周波数応答グラフのx軸は周波数を、y軸はSPL（Sound Pressure Level）を表します。周波数は音の低さや高さを意味し、SPLは音量の大きさを意味します。

理想的なスピーカーの周波数応答グラフはどうなっていますか？

理想的なスピーカーの周波数応答グラフは、20Hzから20kHzまでの範囲で非常に平坦な線を持っています。これは、典型的な聴衆の聴覚範囲です。

スピーカーの周波数応答が±1.5dB以内の場合どう解釈されますか？

スピーカーの周波数応答が±1.5dB以内の場合は、非常に良いスピーカーと見なされます。これは、軸上の応答が非常に平坦であることを意味します。

スピーカーの周波数応答が±3dBを超える場合どう解釈されますか？

スピーカーの周波数応答が±3dBを超える場合は、他のスピーカーよりも優れているとは言えませんが、それでも良いスピーカーです。ただし、周波数応答がさらに外れると、音の色味に影響を与える可能性があります。

スピーカーの低周波数応答が不足している場合、どうすればよいですか？

スピーカーの低周波数応答が不足している場合は、低音の出力を強化する良いサブウーファーを購入することが推奨されます。

Outlines

00:00

🎙️ オーディオデータの意味とは

このビデオは、Aaronのオーディオコーナーのエピソードであり、データの意味を説明するシリーズの一部です。チャンネルの目的は、聴き手が主観的な意見に頼るのではなく、データを提供することであり、Aaron自身がスピーカーを試聴する際の聴き取り感覚を伝えることも含まれていますが、聴き手に客観的なデータと共に提供することで、より正確な情報を提供する狙いです。また、聴き手が好む音や参照音を特定し、最も価値のある選択肢を見つける手助けをすることを目指しています。オーディオレビューアーが主観的なフィードバックを提供するのに対し、Aaronはデータを通じて理解を深めることを目指しています。

05:00

📊 オンアクス周波数応答の重要性

ビデオの中心は、オンアクス周波数応答について説明することです。これは、リスナーの耳に最初に到達する音を表すための共通の出発点であり、多くの状況で公正な表現とされています。周波数とSPL（Sound Pressure Level）のグラフを用いて、理想的なスピーカーは再生システムからの信号を変更せず、同じ忠実性を維持することが求められます。しかし、完璧なスピーカーは存在せず、周波数応答が平坦でない場合、スピーカーは独自の音の特性を加えます。また、人間の聴覚範囲外の周波数帯で応答が変化すると、音の性格が変わることがあります。このビデオでは、スピーカーの周波数応答がどのように音の質に影響を与えるのか、またその線形性とバランスについても解説しています。

10:01

📉 周波数応答の可視化と解釈

このセクションでは、周波数応答グラフの読み方と、±1.5dBおよび±3dBの範囲でのスピーカーの線形性の可視化方法について説明します。±1.5dB以内のスピーカーは非常に良いとされ、±3dB以内のものは良いが最優れものではありません。また、低周波数帯での減衰や、スピーカーの種類に応じた周波数帯の限界についても触れています。特に、低音周波数帯では、多くの书架型スピーカーが出力を減少させることが予想されますが、低音を補強するためにはサブウーファーの導入が推奨されています。このビデオでは、周波数応答の問題点に対処し、レビューでそれらを指摘する際に注意を払う方法が説明されています。

Keywords

💡データ

データとは、事実や数字などの具体的な情報を指します。ビデオの中心テーマは、オーディオスピーカーのデータを提供することで、視聴者が主観的な意見に頼らずに製品を理解できるようにすることです。データの提供は、オーディオレビューの客観性と正確性を高めるために不可欠です。

💡主観的なフィードバック

主観的なフィードバックとは、個人の感覚や意見に基づくフィードバックを意味します。ビデオでは、主観的なフィードバックは聴く人々によって異なる可能性があるため、データと共に提供することが重要だと述べています。

💡客観的なデータ

客観的なデータとは、実験や測定に基づく、個人の感情や見方に基づくことなく得られる情報です。ビデオの中心的なメッセージは、オーディオスピーカーの性能を客観的に測定し、そのデータを提供することで、視聴者が製品をより正確に評価できるようにすることです。

💡周波数応答

周波数応答とは、音響機器が周波数に対してどの程度正確に応答するかを示す指標です。ビデオでは、周波数応答が客観的なデータの中でも最も重要な要素であり、スピーカーの性能を理解する鍵であると強調しています。

💡無響室応答

無響室応答とは、部屋の反射や干渉を排除した状態での測定結果を指します。ビデオでは、無響室応答と室内測定の間には大きな違いがあり、無響室応答はスピーカー自体の性能を知るための重要なデータであると説明しています。

💡軸上の応答

軸上の応答とは、スピーカーが直接聴衆に向かって音を発している場合の音響特性を測定したものです。ビデオでは、軸上の応答がリスナーが最初に受け取る音を表すため、周波数応答の解釈の出発点として重要な役割を果たしていると述べています。

💡dB（デシベル）

dBは、音圧レベルを示す単位で、音の大きさや強さを測定する際に用いられます。ビデオでは、dBを使用してスピーカーの周波数応答の線形性を可視化し、スピーカーの性能を評価する方法について説明しています。

💡 ANSI/CTA-2034-A

ANSI/CTA-2034-Aは、在宅型スピーカーのための測定方法の標準規格です。ビデオでは、この規格に基づいてスピーカーの周波数応答を測定し、その結果を用いてスピーカーの性能を評価していると述べています。

💡線形性

線形性とは、スピーカーの周波数応答がどれだけ平坦であるかを表す指標です。ビデオでは、スピーカーの軸上の応答が±1.5dB以内であれば非常に良いスピーカーであり、±3dB以内であれば良いとされていますが、それ以上になると音の色味に影響を与える可能性があると説明しています。

💡低音

低音とは、音波の周波数が低い音を指します。ビデオでは、低音はスピーカーの周波数応答の低い周波数の部分を表し、多くのスピーカーでは低音周波数の出力が減少する傾向にあると説明しています。

💡サブウーファー

サブウーファーとは、低音を再生する特別なタイプのスピーカーで、通常はスピーカーセットに追加され低音の質と量を向上させるために用いられます。ビデオでは、低音の再現を向上させるためにサブウーファーが必要であると述べています。

Highlights

Aaron's Audio Corner aims to provide data to help listeners understand sound quality without relying solely on subjective opinions.

The channel includes various tests of speakers in different environments to encompass a wide range of listening experiences.

Aaron emphasizes the importance of objective data alongside subjective feedback for a more comprehensive understanding of audio equipment.

Frequency response is considered the most crucial aspect of objective data for understanding a speaker's performance.

Anechoic response measures speaker performance without room influence, providing a pure assessment of the speaker's output.

In-room response differs from anechoic as it accounts for room reflections and other environmental factors affecting sound.

ANSI/CTA-2034-A is the standard method of measurement for in-home loudspeakers, which Aaron's data is based on.

On-axis frequency response is the starting point for evaluating a speaker, representing the first sound to reach a listener's ears.

The frequency response graph's x-axis represents frequency, while the y-axis represents sound pressure level (SPL).

An ideal loudspeaker would have a flat frequency response line from 20 Hz to 20 kHz, matching the typical human hearing range.

Speakers that deviate from a flat response begin to impart their own sonic characteristics, which some listeners may prefer.

Linearity in a speaker's on-axis response is evaluated by how closely it remains within +/- 1.5 dB and +/- 3 dB ranges.

A speaker within +/- 1.5 dB is considered very good, while one within +/- 3 dB is good but not exceptional.

Beyond the +/- 3 dB range, speakers may introduce significant imbalances in sound, affecting the listening experience.

Bookshelf speakers typically have less bass and may show a roll-off below 50 Hz, necessitating a subwoofer for low-frequency support.

Aaron uses the example of the Cali IN5 speaker to illustrate how on-axis response can vary and impact the perceived sound quality.

High-frequency anomalies in speakers can be audibly detected and may influence the overall sound signature.

Aaron's reviews will note any issues with frequency response to help listeners make informed decisions about audio equipment.

Transcripts

welcome to another wonderful episode of

aaron's audio corner

uh this series of videos is going to be

based on providing you with an

explanation of

what the data means

i started this website and this youtube

channel approximately a year ago

the entire purpose was to provide you

with data

the reason i wanted to provide you with

data was so you wouldn't have to rely on

just my subjective opinion

now certainly i'll listen to the

speakers when i test them out and

i still tell you what i hear when i

listen to them in the in the various

fashions you know living room

home theater room near field far field

all sorts of different levels and i try

to test them out all sorts of ways

that way i try to you know encompass

what everybody else is probably going to

be listening

like but the problem with just providing

you with subjective feedback is

sometimes what i hear may not translate

to what you hear we may be listening for

different things you know we may have a

history of picking up on

low frequency elements and somebody else

may have a history of picking up on high

frequency elements

some people may have high frequency

hearing loss so when i provide you with

this

subjective information i want to have

objective data

to go along with that because the idea

is over time

when i provide more and more data you

can start to hone in on hey this is the

sound that i like

or i prefer a reference sound and this

is the best value

to get that or one of the best ways to

get that and then there's certainly

other factors as well like

looks you know the size of the speaker

all these things go together but

the objective data is absolutely

important and it's important to help you

weed through all the fluff because

there's tons of audio reviewers out

there that just tell you

the mid-range sounds warm or the

tweeters sound detailed and it's just

it's superfluous and i don't think that

in the long run that is

as helpful as seeing data and being able

to understand what the data means

it doesn't mean that you have to become

an objectivist it simply means that

you're educated

each of my videos tend to run a little

bit long because i feel compelled to

explain to you

what the data means and in doing so it

just it naturally takes a while to get

through everything because i also feel

the need to break things down on a more

elementary level

so i decided to take my own advice i'm

going to create this series of videos

to tell you what the data means and then

this way you can come back to it when

you look at one of my reviews

and you're curious about you know what

that means i can just simply point you

back to it

i can provide a link in the description

somewhere and say hey if you're curious

about how to read this data and

understand it at a more thorough level

see this series see this playlist so

the first video i'm going to kick off in

this series is going to be frequency

response

because in my opinion that is the

absolute

most important aspect of objective data

without a clear understanding of on-axis

frequency response

you really don't have a grasp on what

all the other measurements mean

so let's get to that before we go any

further i want to clear one thing up

anechoic response is not the same thing

as measured in-room response and what do

i mean by that well it's simply

a lot of people will provide you a

measurement of what they are

getting in their room and then somebody

will say oh i don't like flat in-room

response

you know and they misunderstand that

in-room response is totally different

from

an anechoic measurement an anechoic

measurement is

without the room influence you know the

ceiling floor

walls any of those reflections couch

anything nearby

that would mess up the frequency

response measurement

the reason that you want to separate the

speaker from the room

is because you want to know exactly what

the speaker is doing all on its own

and the reason you want to do that is

because with enough data you can predict

how a speaker is going to perform

in everybody else's room with a high

degree of accuracy

and that's very important i'll point

that out because people will talk about

in-room measurements as if

the same thing is an anechoic

measurement and they are two totally

totally separate things they could not

be further from

different the majority of the data that

i provide is based on a

standard which is this it is the ansi

cta standard

standard method of measurement for

in-home loudspeakers cta

2034-a and

revision 2020 i guess is what this

stands for frankly i don't know

but this document is free to download i

will provide a link

in the description below and you just go

to the website and you give them your

information they'll send you a download

link you can download it and go check it

out and it has

everything that i'm going to talk about

in this video except for a few things

which will be you know distortion and

compression

but for the most part everything that

i'm going to talk about in this series

of videos is going to be covered in this

document

starting with the on-axis frequency

response and we're going to grab from

them

the direct definition of on-axis

response since the contents in this

video are focused on

on-axis sound let me give you an example

of what i mean by

on-axis

this is a speaker the speaker is facing

right at you

that means the speaker is on axis if i

turn the speaker to the side

any direction that means it is off axis

even pointed down would be off axis

there's always a reference plane

typically with most speakers

the reference plane is the tweeter and

by reference plane i mean

where are you putting your ears at like

level wise you know if i put my ears

right here

then vertically my ears are on axis

with the reference plane now if i put

the speaker up here and turn it down

then i'm not on axis with the vertical

plane anymore

so that's just briefly what i mean by

on-axis and we'll talk about off-axis in

a later video

here we are this is the standards

definition for it and i'll read it out

to you

the on-axis frequency response is the

universal starting point and in many

situations

it is a fair representation of the first

sound to arrive at a listener's ears

to kick off this conversation i'm going

to use an example from a recent test i

did on the

cali in5 this is a graphic that has a

lot of information in it but we're going

to focus right now on

the black line that says on axis which

kind of runs through

here first of all how do you read this

graph

well on the x-axis down here is

frequency and on the y-axis

is spl what does that mean

frequency everybody knows bass you know

bass you hear the car

thumping next to you at the red light

your friends are talking about their

subwoofers everybody understands what

bass is

bass is low frequency most people's

voices

cover the span of about 200 to 3 000

hertz so you're talking about this area

right in here that's that's the typical

vocal region for

males and females and certainly there

are some exceptions when you go into the

higher frequencies which is generally

considered you know

one two kilohertz and above going to the

right

that would be sounds of like birds

chirping or

a whistle or the s as somebody's talking

and then when you're talking about how

much there is

that would be covered on this left axis

so for example

if i'm talking quietly then the output

would be in a lower

value of spl and if i'm talking loudly

the output would be at a higher volume

of spl and that's the basics of a

frequency response graph

when you're talking about loudspeakers

ideally what you want

is to not mess with the signal coming

out of whatever your playback system is

so for example

you've got a cd it's got a song on it

and let's say the song

is just a sign sweep and it's that

you've probably heard of sign sweep

before it goes

and that's it right um if the cd has

just a sign sweep on it then the speaker

should play

just the sign sweep only and it should

play it with the same fidelity that is

on

the actual cd medium and that would be

you know a equals b input equals output

unfortunately there is no loudspeaker in

the world that i'm aware of that will

provide you

with that exact thing because there is

no perfect

loudspeaker a perfect loudspeaker would

be a speaker that has a very flat line

from 20 hertz down here to 20 kilohertz

up here

because that's mostly the typical

listeners hearing range

when a loudspeaker gets outside of that

flatline as everyone that i'm aware of

does

that's when they start to impart their

own sonic characteristics to the sound

whether good or bad some people for

example may like a boosted high

frequency response so the high

frequencies tend to sound a little bit

louder

than lows some people like the opposite

some people may want

heightened vocals so they may want more

spl in the 200 hertz to three kilohertz

region so

in this ballpark area right here but the

bottom line again is that there is no

speaker on earth that is dead flat from

20 hertz to 20 kilohertz

at least that i'm aware of and if there

is then that would probably be

considered the reference standard

in terms of on-axis response this

graphic represents

the same black line that you saw on the

previous graphic

however it's just by itself i've got rid

of all the other ones

and what i've done here is i've

calculated the mean spl

over a range of 300 hertz to 3 kilohertz

so basically you know the typical human

voice region

and in doing so i've also said okay now

based on that mean spl what is the plus

or minus one and a half db region

and then what is the plus or minus 3 db

region the reason i've done that is to

help you visualize

how good the speaker's linearity is and

when i say linearity i just mean

you know how flat is the response on

axis

a speaker that is within plus or minus

one and a half db is really

a good speaker a speaker that is within

you know plus or minus 3 db

is a good speaker but it's not the

greatest of the great

and when you get beyond that that's when

you start having issues with you know

speakers really tainting the sound and

creating their own

imbalance in terms of timbre you know

what you hear the vocals may sound

louder than the

high frequencies or vice versa or just

any kind of imbalance overall to the

speaker response

and what i'm looking for here really is

a on-axis response that is well within

the gray window

within limits when i say within limits

what do i mean well

you know most bookshelf speakers are not

gonna have a lot of bass so you're gonna

expect to see some kind of roll-off here

what you do

and you know below what 50 hertz or so

this speaker just doesn't have a lot of

output

that's typical when you're talking floor

standard speakers you're

you're bound to get more output with the

lower frequencies but they still have

their limits

for the most part as well and generally

speaking no matter what speaker you use

floor stander or bookshelf speaker

you're still going to want to buy a good

subwoofer

to hold up and shore up the low

frequency response using this speaker as

an example you can see that it is mostly

within the

and a half db window but it does jump

outside of that at a few points and gets

into the plus or minus three db

window and then when you get to the very

high frequencies it is even outside of

the plus or minus three db window and

you may be wondering

are these effects audible yes they are

if you want to know what i thought about

how the speaker sounded and how

the high frequency you know anomalies

impacted what i heard

then make sure you go check out that

review and i will make sure to put it

somewhere up in the cards if i remember

to and that's it for the frequency

response video

like i said i wanted to keep this one

short and sweet and when there are

issues with the frequency response of

speakers that i've measured i will make

sure to try to note those as i go

through the review

hopefully that helps explain frequency

response a little bit to you and if

you've got any questions make sure you

ask in the comments below