Let's discuss some speaker tweaks to achieve "that" sound

[vivek.saikia]

Hi All,

Let's discuss here some speaker tweaks which will help in achieving a better sound from our existing speakers.
I have personally applied some DIY tweaks to my speakers to make them sound much better. I have stuffed them with dacron fibre to reduce the midbass frequency bump due to the cabinet resonance. You can find the details about the tweak here and here
I have found some minor tweaks being described in this article : Humble Homemade Hifi , wherein the large magnet of the speaker has been covered with felt material to reduce the amount of upper-mid and high frequency energy reflected in the cabinet.
Another tweak which amused me is to short the chassis of the driver to the minus pole of the connector. I am still trying to find out if it really makes any sense??
Thought it would be interesting to know the different tweaks you guys have tried, so please share anything which have actually helped you in improving the sound quality from your speakers.

Cheers!

 

[linuxguru]

If the driver has a paper/cardboard cone, you can stiffen it by applying PVA (polyvinyl alcohol) to the cone, which is widely available in stationery stores as clear synthetic gum. This has the effect of extending the upper-mid response, so it's most useful for full-ranges and mid-bass units.

I have also tried stuffing the cabinet with silk-cotton, which has an effect similar to other filling materials, but more subtle - the fibre mass of silk-cotton is very low, so it doesn't absorb much sound energy, just diffuses it.

 

[vivek.saikia]

If the driver has a paper/cardboard cone, you can stiffen it by applying PVA (polyvinyl alcohol) to the cone, which is widely available in stationery stores as clear synthetic gum. This has the effect of extending the upper-mid response, so it's most useful for full-ranges and mid-bass units.

I have also tried stuffing the cabinet with silk-cotton, which has an effect similar to other filling materials, but more subtle - the fibre mass of silk-cotton is very low, so it doesn't absorb much sound energy, just diffuses it.

Even I had applied wood varnish on the speaker cone, but then I was a 14 year old kid and I had no idea about the science or physics involved. But you know what, the tricked had worked.

 

[captrajesh]

Good thread. I had recently purchased Accoustic Potrait MS101.

They are made with Vifa 6.5" Woofer P17WJ-00-08 and 1" Aluminum Dome Tweeter D25AG-35-06.

Good Drivers, Rock solid build quality but sound! hmm. The mids sounded thin and distant. The highs are trifle grainy.

I wanted them to replace my Modded speakers using Kenwood drivers but no way come close to them in SQ.

Contacted an ever helpful local DIY expert (I'm withholding his name here as I've neither sounded him that I'd be posted about the mod nor that I'd take his name)

As per his advice, we first disconnected the bridge between two terminals and drove just the woofers to get its SQ.

Then we opened up the speakers and connected to the woofer directly bypassing the crossover network. Put on three screws 90% tight)

I could not hear the difference but he said there was perciptable difference. Mids were sounding better but bass was loose.

We then connected even the tweeter (Biwiring the same channel) through its own crossover. The speaker was sounding nice, what the hell not just nice, but lovely.

We repeated the process and connected both the speakers to see the difference.

Mids have really opened up and sounding fuller but the only concern was loose bass.

He did not have much time as he had some other commitments. He said, listen to them for some time and we will tweak em further.

So nice of him to have come to help me in the first place. He didn't even take water though I offered him scotch. (Ofcourse, he was having cold. All the more reason he should have a drink according to me but he didn't budge)

After he was gone, I called my trusted old friend a non-active forum member Sashi Kumar for audition. Poor chap came to me straight from office.

We started our audition in full earnest over a couple of whiskey ke chuskeys.

Hmm, he was liking the mids etc ok but hey, something is amiss he said.

We listened for about 15 minutes.

(Sashi: Why is there no slam. Something is wrong.)

I was like

He said, lets play your towers to check the difference in SQ. He walks upto the speaker to check the mods and notices a thing and says, hey where is the fourth screw of this speaker. He takes a closer look. Why have you not tightened these screws?:annoyed:

This is it he says. Lets tighten these. We did put on all the screws and tightened them fully.

There we go. The tight bass is back, the slam is back.:yahoo:

We listened to the speakers for more than One and half hours.

We need to further fine tune it I'm told.:sad:

Anyway, as one Pizza company ad goes, IM LOVING IT.

 

[gobble]

Even I had applied wood varnish on the speaker cone, but then I was a 14 year old kid and I had no idea about the science or physics involved. But you know what, the tricked had worked.

Hi Vivek

Did you also try pouring wood varnish into your ears? It works better than applying to the speaker cone. hyeah:

 

[gobble]

So nice of him to have come to help me in the first place. He didn't even take water though I offered him scotch. (Ofcourse, he was having cold. All the more reason he should have a drink according to me but he didn't budge)

A tip: Always drink your whisky with water ... and always drink your water with whisky hyeah: esp. when its scotch

He takes a closer look. Why have you not tightened these screws?:annoyed:

This is it he says. Lets tighten these. We did put on all the screws and tightened them fully.

There we go. The tight bass is back, the slam is back.:yahoo:

So screwing tight brings back the slam in life?

More seriously - what does tightening screws 90% have to do with slam?

Cheers

 

[gobble]

Here is tweak that will make you dizzy Loudspeakers installation

Cheers

 

[vivek.saikia]

Hi Vivek

Did you also try pouring wood varnish into your ears? It works better than applying to the speaker cone. hyeah:

And the amicable devil strikes again......... hyeah:hyeah:

 

[vivek.saikia]

Then we opened up the speakers and connected to the woofer directly bypassing the crossover network. Put on three screws 90% tight)

I could not hear the difference but he said there was perciptable difference. Mids were sounding better but bass was loose.

We then connected even the tweeter (Biwiring the same channel) through its own crossover. The speaker was sounding nice, what the hell not just nice, but lovely.

So Cap'n, you essentially fed the midwoofer full freq, and routed the hi freq to the tweeter? This must have changed the sound signature of the speakers completely.
And err.... had the missing screw was some intentional tweak or more to do with something which you were drinking?

 

[captrajesh]

More seriously - what does tightening screws 90% have to do with slam?

Hmm, actually, it does a lot depend on that. Once you remove the driver and do not tighten the screws fully, there is leakage of air from the gaps where the driver is loosely seated.

Seriously, why don't you check it out with the IO2s?:lol:

 

[captrajesh]

So Cap'n, you essentially fed the midwoofer full freq, and routed the hi freq to the tweeter? This must have changed the sound signature of the speakers completely.

Yes, the mids started to sound lush, the tinge of metallic sound to bass is gone, highs which were a trifle harsh have mellowed down. There was an overall improvement of sound.

I'm attaching the frequency graphs of the drivers. If you see, the ideal crossover frequency as per both the graphs, is about 2500 to 2600 Hz which is what the speaker maker did. But the ground reality is different.

If you see the woofer graph, though the response starts dropping after about 2400 Hz, it keeps playing upto 4000 Hz where the SPL level is down 2db. It goes on to play right upto 9000 Hz where the SPL level comes down to 84 db after which, there is a very sharp fall.

The Cross-overs are second order which implies, 12db reduction per octave.

The distant and thin sounding mids is purely because of asking the 1" Dome tweeter to play them than the more capable 6.5" Polypropylene Woofer.

By supplying full range to the woofer thus resulted in better sound.

There is scope of more refinement by changing both the cross overs to limit the tweeter below 5K & woofer above 5K.

And err.... had the missing screw was some intentional tweak or more to do with something which you were drinking?

:lol:While removing the woofer & refitting, the was not fitted in the exact position back (i.e. hole A of the driver was not placed over hole A of the cabinet) This mis-match caused the fourth hole to go out of alignment and we decided to play on rather than figuring out the exact matching as the arrangement was temporary.

 

[linuxguru]

Yes, the mids started to sound lush, the tinge of metallic sound to bass is gone, highs which were a trifle harsh have mellowed down. There was an overall improvement of sound.

...

The Cross-overs are second order which implies, 12db reduction per octave.

...

By supplying full range to the woofer thus resulted in better sound.

...

There is scope of more refinement by changing both the cross overs to limit the tweeter below 5K & woofer above 5K.

Your experience is generally in line with many others who find that it's often optimal to drive the woofer as a full-range (especially if it is 8" or smaller).

You may also find that a simple capacitive 1st-order (6 dB per octave) crossover for the tweeter gives the most natural sound, with no jumping or phase-coherence issues. I have used this arrangement for all my 2-way setups with no problems so far.

 

[vivek.saikia]

Your experience is generally in line with many others who find that it's often optimal to drive the woofer as a full-range (especially if it is 8" or smaller).

You may also find that a simple capacitive 1st-order (6 dB per octave) crossover for the tweeter gives the most natural sound, with no jumping or phase-coherence issues. I have used this arrangement for all my 2-way setups with no problems so far.

I have seen some vintage speakers being supplied with midrange, high range fine tunning knobs. I assume those were having variable crossovers inside. But now a days these variable crossovers are not to be seen.

 

[captrajesh]

Your experience is generally in line with many others who find that it's often optimal to drive the woofer as a full-range (especially if it is 8" or smaller).

I'm glad to know that I'm heading in the right direction.

You may also find that a simple capacitive 1st-order (6 dB per octave) crossover for the tweeter gives the most natural sound, with no jumping or phase-coherence issues. I have used this arrangement for all my 2-way setups with no problems so far.

This is precisely what even Rajiv suggested and what I wrote about further fine tuning. Will surely check that out. What should be the cut off point according to you?

 

[gobble]

I'm glad to know that I'm heading in the right direction.



This is precisely what even Rajiv suggested and what I wrote about further fine tuning. Will surely check that out. What should be the cut off point according to you?

if your mid woofer can go up to 5 or 6K you will get the most of the vocal range without crossover coloration.

Cheers

 

[captrajesh]

if your mid woofer can go up to 5 or 6K you will get the most of the vocal range without crossover coloration.

Oops just realised that the frequency graphs have not got uploaded. Hope it works this time around.

If you see the graph, you can see that there is a steep drop of SPL from 88.5 db @ 3400 Hz to 85 db @ 4600 Hz. Thereafter, it goes steady with an SPL level of 85 db (+/- 1 db) right up to 9000 Hz.

This gives me a chance to tweak the speaker by playing around with different cross-over settings of the woofer from 5000 to 9000 Hz and see how is the going.

Woofer frequency response graph

 

[quad]

If your speaker is really old, it would be good to recap the crossover.

Most cheaper drivers have stamped frames, which can benefit from
damping, using different materials like modelling clay, dynamat etc.

There are some mods like ENABL which have their staunch proponents
(and opponents too, for that matter).

There's lots of info on all these on diyaudio.

 

[vivek.saikia]

Some more tweaks from the Industry experts:

TWEAKS FOR YOUR SPEAKERS

by Steve Deckert
Nov. 1997


To TWEAK: Taking something and altering portions of it to effect better performance. ...also a disease afflicting some audiophiles unable to stop tweaking: audiosystematatweakitis.

A loudspeaker is a necessary evil that is required to convert sign waves into sound waves. It is in most cases a balance of compromise. Many people do not realize that a loudspeaker cabinet is responsible for around 70% of the sound quality and performance. The actual woofers and tweeters are less important than the cabinet if choices must be made. Below are some things you can do vastly improve a speakers fidelity.
SPECIFIC TWEAKS

* Installing strategically located bracing to reduce cabinet resonance makes such a tremendous improvement in the solidness and focus of your sound that you would be amazed.

* Measuring the woofer's specs and tuning the cabinet exactly to that woofer will get you maximum performance with the flattest response. Most are found to be more than 20% in error!

* Carefully reinstall a port that is aerodynamic with flared or rolled edges will remove coloration, wind noise and improve power handling.

* Installing adjustable spikes on the base of the cabinet will reduce or eliminate cabinet rocking which happens on a microscopic level will greatly enhance the focus of high frequencies and the solidity of the bass.

* Installing sound absorbing materials such as cork, or felt on the baffle will reduce rarefaction making it difficult to localize your speakers. This enhances sound stage topology in the stereoscopic array. Makes you speakers have a chance at disappearing when the music is on.

* Reinstalling drivers to be exactly flush with the baffle will improve the flatness of the frequency response of each driver.

* Reinstalling high frequency drivers with composite isolation (poured flexible sealant) tremendously improves the bond between driver and cabinet while at the same time dissipates cabinet resonance into heat so that they do not smear or color the sound from those drivers.

* Reconfiguring the array when necessary and possible to a line source array will usually improve imaging and depth enough to justify the new baffle.

* Installing the tweeter on the top of the cabinet at the proper angle will physically time align the array, completely flatten its response, require less crossover components as a result. Makes your sound stage presentation acquire dramatic depth.

* The worst sound you've ever heard in your life comes from hard metallic chamber created by the magnetic pole piece and voice coil assembly and dust cap. 90% of all drivers I've inspected (1000's) are built with the voice coil former protruding past the cone by as much as a half inch or more. This thin aluminum cylinder rings like any pipe does when vibration is introduced into it. Eliminating this excess and dampening the harsh metal pole piece with a domed felt plug removes perhaps the most major downfall of cone speakers - that cone speaker sound referred to by electrostatic speaker owners.

* Dampening the dust cap or installing a soft butyl rubber dust cap or eliminating it by installing a plug helps hide the remaining nasty sound described above.

* Securely re-gluing the voice coil to the cone can evenly dissipate nasty resonance's from the voice coil into the cone where they can become lost. It also improves the balance and precision of energy transfer through the assembly. About 50% of the drivers that come through our shop were not glued with this precision.

* On woofers - welding the pole piece to the basket rather than the centrally located spot welds, will stop the magnet/pole rocking that happens at high output levels.

* One of the most common tweaks for all drivers (other than tweeters) is the application of anti-resonance pads on the basket. Most speaker baskets ring like a bell when struck, so when music excites the frequency of the basket, the sound suddenly becomes harsh. Vico-elastic dampening laminate, the technical name, is what I use to solve this problem.


courtesy link: DECWARE / Audio Paper - Tweaks for your speakers

The last one seems quite doable and effective too. Will have to try this one.

audiosystematatweakitis Ha ha.........I think that's what had stucked me

 

[gobble]

Oops just realised that the frequency graphs have not got uploaded. Hope it works this time around.

If you see the graph, you can see that there is a steep drop of SPL from 88.5 db @ 3400 Hz to 85 db @ 4600 Hz. Thereafter, it goes steady with an SPL level of 85 db (+/- 1 db) right up to 9000 Hz.

This gives me a chance to tweak the speaker by playing around with different cross-over settings of the woofer from 5000 to 9000 Hz and see how is the going.

Woofer frequency response graph

What are the red green and blue lines?

 

[square_wave]

Good Drivers, Rock solid build quality but sound! hmm. The mids sounded thin and distant. The highs are trifle grainy.

Can I humbly state that there is absolutely no problem with those speakers. That 101s are real gems.The drivers, cabinet and crossover are top class. Do not change anything. You will just screw it up ! I feel you are approaching the problem from the wrong direction.

Feed em a mid-level CA, Nad, Marantz or Arcam amp. It will sing just fine

I personally know a few guys who use them and the floorstanding versions (301's) in hi end systems.

If you want great bang for the buck (much better quality than the mentioned amps above), Please import an appropriate kit from this guy here. I am talking hi-end sound here. The N AKZA 70 or the 100Watt will bring a smile to your face. Guaranteed.
http://www.aksaonline.com/buying/buying_price.html