what makes a speaker timing go awry?

I think it has something to do with phase shifts in the crossover. This happens when voltage and current are out of phase and thus affect the power that is sent to the drivers.

There are more qualified people on this forum who can comment on this. Maybe you should wait for their replies.

Shahrukh schrieb:

I think it has something to do with phase shifts in the crossover. This happens when voltage and current are out of phase and thus affect the power that is sent to the drivers.

I may be wrong, but I think phase shifts primarily affect imaging.

Timing, from what I understand it is the quality if "Catch up" when the woofer cannot keep pace with the tweeter or the midrange thans when you have this problem of the drummer really out of sync with the singer !. I think thats why lighter cone speakers are better at timing .

I am not sure of this, but Amps /source can also affect timing, but thats when they, perhaps, do not send the bass signal at the same time as the high frequency.. but am really unable to think of a technical reason as if they process it at the same time, it should arrive at the same time since the speed of electrons is the same !!

Timing, from what I understand it is the quality if "Catch up" when the woofer cannot keep pace with the tweeter or the midrange thans when you have this problem of the drummer really out of sync with the singer !. I think thats why lighter cone speakers are better at timing .

This is timing, true! But why does it happen? Is it the current/voltage thing or is it something else?

I think Deaf can throw more light on this.

This is what i found at one site

"Time Correction:

Every type of sound wave travels through the air at a constant rate. That means high notes, low notes, and midrange sounds all move from your speakers to your ear at the same speed. But, on their way to the speakers, when those notes are still electrical signals, they travel at different speeds. The low sounds travel through the wires more slowly than the high ones do. This causes timing problems, because the sounds do not arrive at the speaker at the correct time. Good cables and wires fix this problem by slowing down the high notes, coordinating them with the low notes so they reach the speakers at the right time."

http://www.tweeter.com/sm-cable-shopping-guide--bg-1189802.html


Is this funny or wot ?

Here’s a pretty decent explanation from meadowlark audio.
http://www.meadowlarkaudio.com/TC1p.htm

OK from what i understand after some scattered reading.

Timing problem is caused when the different frequencies arrive at your ear at different times as above.

but they could be due to any of the below

1. Room: Acoustics and primary reflections being the cause
2. Speaker: due to speaker design even woofer /Tweeter mismatch
3. Electronics. problems with any filter/Clock in the various electronics .. especially in the source

But would be interesting to see what light deaf/screaminggigi/viren/siva/bhagwan69 are able to throw on this

We really have quite a few tech experts in this forum now

all u ever want to know about time alingment..
here are more articles if u want to go deeper..but this itself is a bit over the top for most forum members.

http://sound.westhost.com/ptd.htm

stevieboy schrieb:

hi all, there's been a lot of posts (read the av show topic) recently talking about speakers not having the right timing. where the bass guy and drummer are not in sync. how and why and what makes this happen? a detailed, even technical explanation would be nice. if anyone thinks its too technical to be posted here, do pm me cos this topic has me really confused :(

Stevieboy,

This could be due to various reasons...

1) Room Acoustics (maginification & cancellation of portions of audible frequency spectrum)
2) Non-uniform frequency response of the speaker
3) Due to the electronics & cables used and not just speaker
...and so on..

I think the discussion on "timing" is in terms of music (a term often used by musicians)...and it need not necessarily be due to "time-alignment" of the speakers..

If you are considering this particular speakers, do listen to it again in a famiilar environment like your own listening room.

Cheers
Siva.

Carry on guys this is great fun .
Regards Deaf

Hi,

I will separate two concepts here - time alignment and coherence.

Time alignement is more or less a physical entity, in that the drivers have to be aligned on a speaker baffle so that their respective frequencies arrive at the listener at the same time. This again is not as simple as it sounds - you have to determine the "acoustic centre" of the drivers, which may not coincide with their physical centres (often approximated as the dust cap). And, as the "acoustic centres" vary with the reproduced frequency, you are back in the hunt. A sloped baffle does not guarantee time alignment! Nor coherence of sound.

Coherence is more of a subjective experience. And probably more in line with what Steve was asking about. The bass sounding disconnected, lagging the mids and highs. I suspect this has to do with the drivers and the associated crossovers, and also the speaker cabinet (anything else left!). Bass drivers whose cones are heavy, cone materials that store energy and release it at lower frequencies causing time smearing, cabinets walls that are not damped and contribute too much to the speaker's sound - these colour the sound mainly in the low frequencies. This gives a bass a "heavy" sound, the articulation is lost, and it becomes disembodied from the rest of the sound. The bass player lagging behind!

No getting away from good, integrated speaker design!

Viren.

deaf schrieb:

Carry on guys this is great fun . Regards Deaf

We're waiting for your comments on this one, Deaf!

thanks for all the replies guys.. and square wave, arj and newtohifi for the links. will read up at leisure in the evening.

well viren u got it right i was more thinking about time coherence. in particular how can a bass guitar and a drum sound time incoherent since the driver is the same? is it cos of the crossover order that delays different frequencies and causes time smearing?

that was more the intent of my question. cos a i heard a dynaudio audience 42 and a psb something and the guy was insisting that the dynaudio's timing was way off. he kept urging me to listen to the bass guitar and the drummer and that the timing of the two was different. wonder how that happens?

and deaf yeah get off that fence stop smiling and put in a detailed reply!

Hi guys,
Well Shahrukh heard the difference,so I guess it does exist,because I can hear it immediately. :).Sorry, this is fun, for once the fence is comfortable.Stevieboy is going to kick my butt off this fence in the next post ,till then .I love it when you chaps enjoy audio so much.
Regards Deaf.

no deaf, have changed my mind. not going to kick ur butt off the fence. will just initiate a poll to rename u humpty dumpty

u still have time to post before all the kings men come...

stevieboy schrieb:

no deaf, have changed my mind. not going to kick ur butt off the fence. will just initiate a poll to rename u humpty dumpty u still have time to post before all the kings men come...

AAARRRGHHH,He sounds like my wife .
Mischevious Stevieboy .
Regards Deaf

Dear Stevieboy,
Just read the post to my wife,she is amazed at your clairvoyant abilities,Humpty Dumpty is apt she says.You me dude.
Regards Deaf.

A smart Humpty will remain en-position even if the Wall falls down :).
I would rather look at it as an Objective and dispassionate view on the proceeeding

[/quote]A smart Humpty will remain en-position even if the Wall falls down .
I would rather look at it as an Objective and dispassionate view on the proceeeding


Arj,
Is this the Paris effect? You seem to be becoming more and more profound with each new post

Keep it up.You are well on your way to becoming the resident Bodhisattva, of atleast this forum.

If an enclosure has 8 Ohms nominal impedance and if it has twin woofers, does it mean that it has two 16 Ohms drivers in parallel?
How do they manage if there are 4 woofers (i read that its not good to connect drivers in series)?

Does the way speakers are connected contribute to phase difference?

deafDear Stevieboy, Just read the post to my wife,she is amazed at your clairvoyant abilities,Humpty Dumpty is apt she says.You me dude. Regards Deaf.

well deaf it was purely a reference to humpty's penchant for eschewing sofas and other comfy things in favour of a wall.

but since it apparently has other connotations, u can tell your wife that she's being far far far from politically correct. it's actualy "enlarged physical condition caused by a completely natural genetically-induced hormone imbalance" and thereby steer the topic of discussion into safer waters like zany politically correct terms you have come across

Dear Stevieboy,
Man I said earlier you will kick my butt off the wall,so you did.
It is very easy to talk about timing with regards to loudspeaker design very difficult to perceive it.It is not an important aspect to most audiophiles,as they are simply not aware of it. Musicality, soundstage,imaging etc etc,are given a higher priority and rightly so,because this timing aspect only dawns upon you after many years of listening to various systems,that too when that one speaker, when it hits you with correct timing,it is like a floodlight out of total darkness.
What gives one speaker better timing thananother?Frankly, with all due respect to Viren's explaination,which every good speaker designer is aware of,still some chap ends up making a speaker superior in this regard than most.Inter driver timing apart,with the same driver playing,still there are timing issues e.g.Bassist with Drummer(this shit is getting old),same driver right?still some speakers time better than others with regards to this.
Why is this idiot Deaf talking all this crap?Because Deaf only can hint at the answer.Settling time is the answer.Settling time of every component in the loudspeaker that is,enclosure,drivers,crossover components,port material, the compressed air in the enclosure(the same driver can be placed differently in the same enclosure and so can the port,whereby the air mass will react differently).All these aspects (driver ,enclosure,crossover ringing,wadding, port etc etc) have to work as one,complementing each other, in a loudspeaker for it to time correctly, and not against each other,which is bound to happen in a speaker due to forces working against each other.Only many years of loudspeaker design experience can give one the ability to design speakers with correct timing abilities,that too if the designer considers it a priority.I hope that answers the issue to a large extent.Thanks for your patience.
Regards Deaf

viren schrieb:

Hi, I will separate two concepts here - time alignment and coherence. Time alignement is more or less a physical entity, in that the drivers have to be aligned on a speaker baffle so that their respective frequencies arrive at the listener at the same time. This again is not as simple as it sounds - you have to determine the "acoustic centre" of the drivers, which may not coincide with their physical centres (often approximated as the dust cap). And, as the "acoustic centres" vary with the reproduced frequency, you are back in the hunt. A sloped baffle does not guarantee time alignment! Nor coherence of sound.

Viren,
Could you please expand on acoustical centers of drivers and how it is affected by the placement of the drvers on the baffle?

a few more things,
we all know that surface mounting a tweeter is a huge NO NO!

we also know that the dispersion patterns of an MTM differes from a convetiona TMM.
Is this the acoustical center that you are talking about.
The center of teh dispersion region of the different drivers based on their position on the baffle.
How would it differ for a Line array?

Viren....

And also on approximation of acoustic centres....

manek.

Deaf,

Assuming this is a problem with the speaker...agree with you. Only the scope of the problem is a bit larger....

1) Time Delay - Between Stereo/Multi-Channels
2) Dynamic Range
3) Transient Fidelity (like you've mentioned here)
4) Non-Linear Distorition (like Viren has mentioned)

All of the above mentinoned affect various aspects of the music including timing.

Today, with the availability of sophisticated measurement equipment using the computers, it is possible to measure the performance of a loudspeakers against these factors. But it helps only to some extent and like you said it is still very immpreative to have that listening sessions with expereienced listeners.

Cheers
Siva.

Acoustic Center of a driver:

It will be on the Z axis of the baffle; For a woofer it is generally behind the baffle (point where the spherical waves seem to diverge from, alternatively point from where the SPL varies inversly to the distance) and idealy for the tweeter it is bang on the baffle. The challenge is in properly alignining the phase charactertics of both woofer and tweeter. Dependending on the size of the woofer (the relative distance between the woofer and tweeter's acoutsic center), the baffle might require to be tilted. It get's more complicated, as the crossover too affect these acoustic centers.

Measuring acoustic centers are not a trivial tasks. For those who are intrested, please send me your mailing address and i can send across hardcopy of a white paper from engineering society that has the required formulas and methods.

Cheers
Siva.

I've corrected a typo .."Z" axis, which would have been apparent from the description; Also removed wrong usage of words in defining the acoustic center....sorry wrote this message early morning before my coffee..

sivat schrieb:

Acoustic Center of a driver: It will be on the Y axis of the baffle; For a woofer it is generally behind the baffle (point where the spherical waves of different length seem to diverge from, alternatively point from where the SPL varies inversly to the distance) and idealy for the tweeter it is bang on the baffle. The challenge is in properly alignining the phase charactertics of both woofer and tweeter. Cheers Siva.

But, does this hold good for all types of tweeters. How would it be for a ribbon or planar or even a horn tweeter.

What do you use to calculate the acoustic centers for soemthing like the Heil AMT or the Oscar AVT?

Regarding the woofers, what do you do for Passive radiators and coaxial drivers and drivers like the Lowthers with 'whizzers'.

How would you do the acoustical centers and measurement of placement on the baffle based on that. There are more issues to decide this but limiting to acoustical centers what would be the guidelies for these types of drivers?

Deaf, Assuming this is a problem with the speaker...agree with you. Only the scope of the problem is a bit larger.... 1) Time Delay - Between Stereo/Multi-Channels 2) Dynamic Range 3) Transient Fidelity (like you've mentioned here) 4) Non-Linear Distorition (like Viren has mentioned)

whoa there siva you're opening a new can of worms now. can you expand a little on how dynamic range affects timing? by the time delay between stereo and multi channel i presume you're referring to the front two speakers and inputting delay for the rear speakers in multi channel. is that right?

thanks.

well deaf you got off that wall just in time

Stevieboy,

Deaf explained about how a bad transient response character affects the perceived timing. A crude way of looking at it would be "exaggerated sound"

Lack of Dynamics, has the opposite effect...information is lost. This loss of information will make it difficult for the listener to co-relate the different instruments and even the musical-tune..

As far as the basic problem of "timing" is concerned, it is not a result of one of these factors. It could be due to a combination of these. In the particular instance you are saying, it is very difficult to say that "this is the source of this problem"...but requires careful study of these factors by measuring them.

Also, you should not that this could also be affected by your electronics. For example - i'm sure every one knows that impedance vary's with frequency...and most drivers exhibit a much lower impedance in the lower frequency spectrum. Many amps cannot properly control the drivers at these lower frequency, as well as they could do in the mid-range, due to this change in impedance. This can also cause the problem that we are talking about here..

Cheers
Siva.

Master Yoda,

I have no expereince working with either Lowther or ribbon/planar tweeters. But i would think the same principle of acoustic center would apply here.

Where it would be different would be when you start thinking about dispersion/directivity index and its impact on the interaction with other drivers..

Cheers
Siva.

sivat schrieb:

Master Yoda, Where it would be different would be when you start thinking about dispersion/directivity index and its impact on the interaction with other drivers.. Cheers Siva.

Dispersion and directivity index is the same as in Radars..
I know that a lot of the same physiscs is put into analysing speakers as well. But i feel the acoustical centers and dispersion pattern(very much similar to the coverage of a radar) and the direction of maximum intensity being the directivity index are pretty much very closely related. i only wonder how these differ when say, ribbons and dome tweeters are considered.

Like in a dome maximum dispersion is on the z- axis or otehrwise known as on axis resoponse.
we know that the off axis response 30 and 60 degree responses are inferior when compared to the on axis response.
how does the ribbon's response fare when compared to that of a dome tweeter. what are the moutnig techniques, constratints in dome and ribbons.
Stuff like that.
how do you determine the flare of the horn , should it be single flared or double flared.

thanks siva that cleared it up. was thinking on the same lines but thought u had meant something different

sivat schrieb:

Deaf, Assuming this is a problem with the speaker...agree with you. Only the scope of the problem is a bit larger.... 1) Time Delay - Between Stereo/Multi-Channels 2) Dynamic Range 3) Transient Fidelity (like you've mentioned here) 4) Non-Linear Distorition (like Viren has mentioned) All of the above mentinoned affect various aspects of the music including timing. Today, with the availability of sophisticated measurement equipment using the computers, it is possible to measure the performance of a loudspeakers against these factors. But it helps only to some extent and like you said it is still very immpreative to have that listening sessions with expereienced listeners. Cheers Siva.

Dear Siva
We are only talking speakers here.I have the ability to negate all other aspects of the chain when I want to listen to a particular component,including the room.
In mono, point no 1) is meaningless
Below 75dbA, point no 2)holds no weight in modern loudspeakers.
All tranducers and capacitors have non linear distortion,it is only how well you control them,which in other words mean how good is your transient response.That is not all though,It is how each aspect of the loudspeaker settles and compliments each other.As I said many many years of experience,and if you can hear it at all,because believe me it is very easy to talk about,but very few people I have come across who can actually perceive it.If I have offended anybody please forgive, me as this is one topic very close to my heart and thereforeI would have preffered sitting on the wall.See what I mean Stevieboy.
Regards Deaf

[quote="Master_Yoda"]

Dispersion and directivity index is the same as in Radars..
I know that a lot of the same physiscs is put into analysing speakers as well. But i feel the acoustical centers and dispersion pattern(very much similar to the coverage of a radar) and the direction of maximum intensity being the directivity index are pretty much very closely related. i only wonder how these differ when say, ribbons and dome tweeters are considered.

Like in a dome maximum dispersion is on the z- axis or otehrwise known as on axis resoponse.
we know that the off axis response 30 and 60 degree responses are inferior when compared to the on axis response.
how does the ribbon's response fare when compared to that of a dome tweeter. what are the moutnig techniques, constratints in dome and ribbons.
Stuff like that.
how do you determine the flare of the horn , should it be single flared or double flared.

Master Yoda,
You really think a lot I must say .If you are designing a speaker then stick to the domes,as they work best with cone devices and are closest in principle too.The ribbons and horns are too different from cones, and are best used when they are covering upto 250Hz at the least whereby, the room power response can be somewhat equal upward from here.Using these two technologies for the upper octaves only, is very complicated,as it not only has directivity issues, also the acceleration of the HF diver will be vastly superior to the LF driver,if it is a 3 way speaker with a large woofer.
This Jazz could go on for ever,but finally most of us end up with a cone and a dome,when it comes to serious listening.
Regards Deaf.