DIY Open Baffle Experiment

[jaudere]

Definitely worth trying. Try it first without dismantling the speaker and then of the driver alone. Even we will learn how the baffle affects the sound. By the way, the graph of your laptop speakers appears ghastly! Tell me exactly what equipment/software you use. If possible, i will try to gauge my speakers as well.

 

[aashish351]

Join home theatre shack forum and go to there downloads section and get the RoomEQ Wizard Software. It's one of the best measurements software and it's free!

Ideally you need a calibrated microphone and an SPL meter for perfect results. But I will have to make do with the laptop mic for now. An external USB soundcard is also better.

 

[aashish351]

Definitely worth trying. Try it first without dismantling the speaker and then of the driver alone. Even we will learn how the baffle affects the sound. By the way, the graph of your laptop speakers appears ghastly! Tell me exactly what equipment/software you use. If possible, i will try to gauge my speakers as well.

Didn't work out... I think the mic in the laptop distorts after 10 kHz and before 100 Hz. I tried to measure my Dali Ikon 6 first as they were already connected. A ghastly curve just like the one I posted above. It is the mic. I will have to arrange a proper mic. only then the curves will have a meaning.

 

[Sumanta]

I think there will be some way to play certain frequencies through laptop from net or from some free programme. Then you can listen it and judge to your expectation.

 

[aashish351]

Yes, there are Test tone CDs and literature along with them. But at the least, an SPL meter is required to see which tone has what SPL so that a manual graph can be made. a hunt for a budget SPL meter begins...

 

[jaudere]

Pyle mini SPL meter is available in Panjim but cost is 4k. I am not ready to put that much money till my ears tell me that there is something wrong in speakers.

 

[aashish351]

Actually it all starts from your ears telling you that something is wrong and then you want to know what exactly is wrong.

I believe that speakers+room are supposed to disappear and not draw your attention from music to themselves by doing something wrong. In my case, a high energy vocal clip or some piano notes in the same range, glare a little too much to be unnoticed. And that's what I am after if I want to continue to enjoy my open baffle speakers. I am open minded and this effort could lead to any possibility from changing driver to tweaking baffle to treating room even!

 

[aashish351]

Another mistake I think I have done is that I did not specify which board the carpenter should use... He has used the commerical board which has wooden strips sandwiched between plyboards and the strips have gap in them. I should have gone with MDF or GreenPly kind of solid board. When I knock the baffle there is ringing hollow wood sound (not a lot but evident).

 

[jaudere]

It is possible to fiddle a bit with tone controls to tame down the mid range? If you are using a computer as source, it is easy. Otherwise you may need equalizers or the tone control labelled as 'mid' on the amplifier. This will be much easier than changing driver/room acoustics and should be tried first (may be you have already tried it). By the way what is distance between back wall and speakers?

 

[aashish351]

assuming by back wall you mean wall behind my back... speakers are placed 3 ft from front wall and 23 ft from back wall in a 26 ft long by 14 ft wide room. Seating position is 8 ft from speakers, 11 ft from front wall, 15 ft from back wall. speakers are 8 ft apart and 3 ft from side walls

 

[jaudere]

Another mistake I think I have done is that I did not specify which board the carpenter should use... He has used the commerical board which has wooden strips sandwiched between plyboards and the strips have gap in them. I should have gone with MDF or GreenPly kind of solid board. When I knock the baffle there is ringing hollow wood sound (not a lot but evident).

Don't worry much about the ply. Open baffle design is most forgiving about wood material and dimensions. I was even thinkg of using acrylic for baffle but it was becoming way too costly. I may still try it. Transparent baffles will look so cool and there is no question of any dampening material. Consider your present baffle as your test baffle. The material is good enough. Even I had thought a lot about using celing speakers but gave away the idea. Another good option is using car speakers. Car speakers mounted behing rear seats work on 'infinite baffle principle' which is very close to open baffle. I tried el cheapo 4" sony and pioneer car speakers but wasn't very happy but I am sure that good quality and bigger car speakers will do well on open baffle. For coaxial car speakers, you don't even need to buy separate crossover. The cap for tweeter is built in. Coaxial design is supposed to be best to have point source of sound and supposed to give better imaging.However sensitivity of most car speakers is less than 90 and impedance 4 ohm. Don't know how much it dips down. My marantz amp did not have any problem but it may not be very safe for home amplifiers. It is ok for car amps because they are made to tolerate even 2 ohm load. M

 

[aashish351]

Can try a car audio driver... but i will need to make a new baffle since the baffle hole is 8.75" for the current ceiling speaker mounting which will probably be more than any 6" car speaker.

 

[Hari Iyer]

Can try a car audio driver... but i will need to make a new baffle since the baffle hole is 8.75" for the current ceiling speaker mounting which will probably be more than any 6" car speaker.

I will advise you against using any car speakers as they are not that refined compared to a home speakers and you could miss on details. The mid-range is too harsh and the bass sounds too artificial. If you still want to use a car speaker settle for some kevlar cone types if possible.

 

[jaudere]

What Hari says is correct. The car speakers use different cone material to be sturdy and can have higher moving mass for same size as compared to home audio speakers. However, good quality car speakers can be tried although they won't be cheap. You may need to spend upwards of 6k for a pair. As I said, I have already tried cheap (but branded) car speakers and was disappointed. Even Ahuja is known for public address speakers where high sensitivity is more important than quality of sound/finesse. so I had doubts about their performance. Still I took a plunge and bought the full rangers but they were lot cheaper than good car speakers. 2800 per pair. I liked the sound. After all whatever floats your boat is good for you.

 

[aashish351]

I did get the 12" ahuja full range for trial... but by playing them side by side with focal ceiling speakers in open air, I found them to be equally glaring in the midrange while the detailed high frequencies of focal 2 way coaxial were missing from ahuja. So i decided to not keep it... maybe mounted in the baffle they sound better! But, if the focal ceiling speaker doesn't work, I will try to get other hi-fi drivers like peerless, dayton, hi-vi, tang band etc. or full rang like fostex.

 

[jaudere]

Ahujas will perform poorly in high frequencies. That is expected. That is why I needed to add tweeter. By the way, what is the cost of your focal speakers? Fostex is in a different league but it would be difficult to call Tang band/Hi vi/ Dayton as Hi fi. At least by the prices,they seem to be low end and your focal may in fact be better than these. Altec/JBL/Vifa/Wavecor will have better drivers. So in case you are importing drivers, go for better ones. There is another option you may try. Try adding a driver for bass. As I had said, may be midrange is prominent because bass is bit weak. What you can do is add another driver for bass duties. You will need a woofer (in fact you can use that full ranger that you got on trial basis) and low pass filter. While Ahuja has 250 hz Low pass filter, part express had 100hz low pass filter. In case you need ahuja low pass filter, I can give one to you on trial basis.I will closely follow your experiments. By the way, I am unable to accept Friend request due to technical problem. It is not accepting 'save change' option.

 

[aashish351]

The focal ceiling speakers were 8k a piece in 2006. They sound very neutral, flat and detailed from nearfield. Thanks for the Vifa/JBL/Altec suggestion... you are right. It will be worth upgrading to those drivers only... but I might try a peerless in between, only because it is locally and economically available.

I am a little confused about the less bass making the midrange glaring... In vocal oriented music where there are no bass notes being played, only voice, piano or guitar, how would the subwoofer or bass driver make a difference?

Thanks a lot for the offer... there is an ahuja dealership very close to my place and existing supplier for my office PA requirements, so I can take anything from there and even return if not suitable.

 

[jaudere]

I tried something new today. My right tweeter was having some problem due to loose connection. I decided to change cable to good one. The local hifi shop was closed so I went to local eletcrical shop. While searching, I found a thick monofilament cable there. The shopkeeper told me that it is used for earthing. Bought 2 metres for Rs.28 . To look for change, I changed internal wiring of only 1 speaker (from speaker terminal to full ranger and from full ranger to tweeter replaced with this new earthing monofilament cable). Guess what, there was a HUGE improvement. I heard few songs whiel changing left to right intermittently. The separation of instruments was superb and the lower and higher frequencies were better with more improvement in the higher ones.. Previously I used to keep either Loud switch of my amp on or I neede to use equalizer for lowermost frequencies on Foobar. Now I don't need either of these. To be doubly sure, I fed right speaker with left amp channel and vice versa. The superiority was persistent. The speaker with new cable was far better than the other. It was as if there was some veil on one speaker while that on the other was removed. The background score now could be easily heard separate from main voice. Guitar strumming was much clear. Cymbals were crystal clear with nice long decay, the initial sound of 'Radha kaise na jale' from ' Lagan' gave goose bumps and mind well, this difference was appreaciable between right and left speaker. So it was direct A/B comparison and not comparison of present experience with past. My family members who did not know that I had done modification unanimously chose the speaker with new cable as the better one. such a huge improvement cost me only Rs 28. . I don't understand why this happened. Either my previous internal cables were of poor quality or this monofilament cable has to do something with it. Need to read further. Hari and other Gurus, can you please explain this phenomenon? Is monofilament cable superior in conduction?

 

[aashish351]

Not sure about the mono filament cable but good cables do make a considerable difference. When I upgraded from a cheap cable to the chord silver screen and then to atlas hyper I could hear considerable improvement in both cases. But thanks for the idea... Will try.

Sent from my Nexus S using Tapatalk 2

 

[Sumanta]

I think I now understood what you meant by monofilament. Earthing cables are probably made to have low resistance. I think your drivers were not getting good power flow.
The difference in their quality must have been huge.

If you can, it is better to connect the full ranger directly with the amplifier to reduce one joint. Tweeter any how need to be connected from the full ranger in series.