My experience of the day with Mr. ravindra Desai and his surround/stereo system.

[Ravindra Desai]

Sorry, I was logged in but was attending to some guests.
I'll try to answer your questions that were specific to the gear and algorithms.

But before I begin, I have to mention something about Tuff in public that I did in private:
He got bored for half a day and still kept looking for what he could like. He thus has been an ideal examiner/ reviewer and I was lucky to have him.
Also, while I was with him, he never showed his feelings thus keeping my morale up all the time.
So, again, thanks a lot Tuff!!

Wow, feels good to hear. Can you add a bit on how it sounded compared to auto caliberated sound from AVRs? Did you experience any audible difference?

Exactly my question too...can mr.ravindra's box act as a pure preamp. I would love to hear how it compared to a proper avr

I am currently using an AVR without any calibration. So, it took a lot of iterations for me to get the right gain mix between the front and back speakers. Also, this mix needs to be changed whenever I switch from Indian movies to English movies. Hence I wanted to understand how DSP handled the volume normalization. I am a fan of lesser buttons. Also, the preamp capability question from the other FM opened up an option of pre-power route. So, this system is definitely intriguing. I am glad that you, Hari and Ravindra were able to meet. Thanks for the detailed review and answers to all the questions posted!

It is proper AR not an AVR. These days, the V part is handled by the TV/ projector. e.g the HDMI switching. So I did not feel the need to include it.
A regular AVR has auto-calibrate! So what does it calibrate? Differences in speaker tones (EQ) because the speakers are different, impedances (Gain), distances (delays) and in the process accounts for room acoustics also.

What if the speakers were all the same and its placement correct?
Then I would not need EQ, Gain and Delay adjustments, right? My speaker system is exactly that and the 2.1CH configuration does not allow for wrong placement. So in a way mistake proof (Poka Yoke)
Now for the controversial room acoustics correction: Should the room acoustics be treated using electronics or using sound absorbing material? Why over-ride A.R.Rahman just because your room is not acoustically correct?
But perhaps the biggest dis-advantage of auto calibrate is that you have to do it every time you change the curtains, seating position, speaker, amps etc. making it very set-up specific. More over it leaves a bug in your head if you are best calibrated at that specific moment diverting you away from your content.

My system continuously senses the incoming signal (DSP does this) and impedance (amp does this) in run time and does the required corrections automatically, internally, leaving you in peace at all times.
Do you use different speakers for stereo and keep it asymmetrically? Then follow the same for Surround listening.

About volume normalization: The DSP checks for loudness of a sound passage (not a particular frequency which would make it frequency specific) and compares it with the set volume level (master volume) and corrects the passage volume level to match the set volume level. This allows you to hear the faintest of night bug and the loudest of explosion w.r.t the set volume level without hampering the impact of either.
Yes, this feature is also a part of my DSP.

Ravindra also mentioned that he had programmed the DSP in tune with the speakers he had brought.( Something he can perhaps elaborate more upon..).

Based on the resonance frequency of my full range speakers, I set the crossover frequency.
Based on the resonance frequency of my subwoofer, I set the subsonic frequency cut-off (High order HPF cut-off).
Based on the power rating and sensitivity of both, I set the relative and total gain so that at full volume the amplifier does not clip nor the speakers distort.
I do not do any frequency related correction as it would make it speaker specific.

@tuff - How do you rate this for Stereo listening ? I understand that the system has impressed you with its surround capabilities but would like to hear more about its Stereo capabilities.

I admit I was, and apologize for being adamant about using MP3 and analog line out from PC.
Changes to the input signal chain (better source and source material) will greatly improve the stereo performance also. I regret not carrying the SPDIF input module with me.
With that said, as Tuff rightly mentioned, my speakers are my weak link. I admit it.
But I need something to demonstrate my electronics and still be able to fearlessly carry it in MSRTC bus and keep it portable.
Packing and unpacking these 6 times in a day was not easy. But at least I was not nervous of scratching them or breaking them and would not worry much even if I did.
Also, I admit that I was worried that if I carry the best of speaker system package, I would not be able to convey the role of my electronics in the resulting system quality.
Yes, better the speakers, better will be the system performance, both for stereo and surround.

a small doubt, if I disconnect my Front Speakers in AVR, and keep only Surrounds and center, and changing the Center speaker to Large with Recaliberating the Audessey will the effect be nearly same ? @elangoas could pitch in ..

With my 2.1CH surround processing there is loss in panning but no loss in content even if there is no L and R channels.
You can try it with your AVR but you have to let auto-calibrate engine know before hand that you don't have L and R, else you will loose content.

I hope that I have covered all your answers. There were posts submitted even as I was typing my answers. So kindly let me know if I missed anything.

Wow! Thanks to all for your interest!!

Regards,

Ravindra.

 

[VSTEREO]

But I need something to demonstrate my electronics and still be able to fearlessly carry it in MSRTC bus and keep it portable.
Packing and unpacking these 6 times in a day was not easy. But at least I was not nervous of scratching them or breaking them and would not worry much even if I did.
Also, I admit that I was worried that if I carry the best of speaker system package, I would not be able to convey the role of my electronics in the resulting system quality.
Yes, better the speakers, better will be the system performance, both for stereo and surround.

Rightly explained. Thank you!

 

[elangoas]

but home theater AVR's always seem flimsy

HDMI boards blowing up is perhaps the most common problems we face on this forum.

Though my reply is off-topic to this thread here, thought of mentioned few things.. AVR does a LOT than stereo amplifiers.. So probability of AVR failures is more IMO.. I have had a faulty HDMI board experience with my AVR..

Just look at Norge, what a great example that is for the Indian audio industry. people have used those amplifiers for decades and they still perform at their best. How many companies can claim that?

No disrespect to any Indian hi-fi manufacturer.. Forget HDMI, Norge hasn't made an amplifier with digital inputs.. Sonodyne at-least has few models, though not many with HDMI..

What is the most exciting audio product from both these companies?.. Where is a soundbar ?.. Where are amplifiers with digital inputs?..

It is extremely disheartening to see none of the Indian companies innovate products inspite of a huge untapped potential..

Alternatively, we can reduce the level of Front Speakers to negligible volume and set the Surrounds level to higher volume and try if we can achieve something similar ; basic idea being, dialogues and straightforward audio effects from Center speakers and background music /ambient sounds reproduced by surround speakers!

Even if we reduce the speaker levels to the lowest for fronts, It will not play as you intend to.. As the fronts are still getting the decoded signal from AVR..

The closest would be to set the fronts as "none", then there is a possibility of "center" channel receiving all the information..But, am not sure if this is possible..

@Ravindra Desai, am proud of you for what you have achieved with your set-up coz not even a single Indian hi-fi audio company have taken efforts to make something like this..

 

[Hari Iyer]

We had also briefly connected my open baffle speakers to the amplifier. As the AR had fixed crossover of 250 Hz tuned to his puny speakers, the setup sounded very compressed in the mids and highs. Proper system matching is required and you cannot just go with any speakers I presume with this setup.

Also connected my micro- TL, but the magic was not there in stereo listening. The synergy needs to be designed and built imo. Correct me Ravindra if I am wrong.

 

[Ravindra Desai]

We had also briefly connected my open baffle speakers to the amplifier. As the AR had fixed crossover of 250 Hz tuned to his puny speakers, the setup sounded very compressed in the mids and highs. Proper system matching is required and you cannot just go with any speakers I presume with this setup.

Also connected my micro- TL, but the magic was not there in stereo listening. The synergy needs to be designed and built imo. Correct me Ravindra if I am wrong.

Hello Hari,

I had got my DSP pre-programmed for 2.1CH configuration for both stereo and surround
I wanted to program the DSP in your house for 2.0CH Stereo to drive the Open Baffle and uTL speakers. This way you and Tuff could also get an idea about the re-programming process. Due to time crunch, we could never get there and we had to rush through all the combinations just to get an idea of each one.

So what we really did was drive the OBs and uTLs with bass diverted to the sub-woofer channel whose sensitivity and impedance was way off from the pre-programmed parameters.
For this reason, I would not draw any conclusions for the combination where my electronics was driving your speakers.

Similarly, but for different reason (20Wrms was too small to move Tuff's Magnepans 1.7), I would not draw any conclusion how his speakers sounded with my electronics.

So you are correct when you say the synergy was not there because of improper bass management.
Hopefully, I will make another trip where we could do due diligence to the configurations where we had to rush through.

Regards,

Ravindra.

 

[drkrack]

With my 2.1CH surround processing there is loss in panning but no loss in content even if there is no L and R channels.
You can try it with your AVR but you have to let auto-calibrate engine know before hand that you don't have L and R, else you will loose content.

Did try it in the morning, because I had to rerun audessey due to furniture adjustments , but Audessey is not accepting calibration without Front channels (Logically it makes sense). Will have to Connect Surrounds to Fronts on AVR , Set Surrounds to 'None', recalibrate and see (Postponed for Sunday hopefully)

Even if we reduce the speaker levels to the lowest for fronts, It will not play as you intend to.. As the fronts are still getting the decoded signal from AVR..

Yes I realized it, I Got Seemingly different results, with keeping the surrounds slightly overpowered than front speakers, same movie track appears bit different now. appears better in action scenes etc

@Ravindra Desai, am proud of you for what you have achieved with your set-up coz not even a single Indian hi-fi audio company have taken efforts to make something like this..

Yes Cheers to that, that too in a highly competitive segment at the moment, Kudos. Simplifying the things to suit Indian Scenarios is the key USP here.

Hopefully, I will make another trip where we could do due diligence to the configurations where we had to rush through.

By the way Even Hyderabad is not far from Kolhapur , (I will try to meet you if possible, during my Next Belgaum Visit)

I had got my DSP pre-programmed for 2.1CH configuration for both stereo and surround

I was wondering if you could Just Make the Preamp version of your AR, So user gets the flexibility in deciding the amplification and Speaker signature of his choice, Just an optimistic thinking further, if you could incorporate the digital inputs and your version of digital Phono inputs into the Preamplifier (Rather - Pre processor to be specific) it will cater to requirements of many. Some People can use 3 Powered Speakers & Active subwoofers or 3 Channel Poweramp + Active Sub to get the desired effect. Best of Luck with your future endeavours

 

[Hari Iyer]

The preamp version of the DSP is a very good suggestion. Users already having an AVR can use the analgue EXT IN input to power all the 5 channels and the subwoofer from this DSP preamp signal. Cost and overhead of an additional power amps can be saved. Also you get to use your current speakers.

 

[blackscorpio]

I was wondering if you could Just Make the Preamp version of your AR, So user gets the flexibility in deciding the amplification and Speaker signature of his choice, Just an optimistic thinking further, if you could incorporate the digital inputs and your version of digital Phono inputs into the Preamplifier (Rather - Pre processor to be specific) it will cater to requirements of many. Some People can use 3 Powered Speakers & Active subwoofers or 3 Channel Poweramp + Active Sub to get the desired effect. Best of Luck with your future endeavours

sounds like a good idea. I guess Ravindra Desai's system is already very economical, only preamp version would possibly cost much less. That makes it very affordable just to try it or have a second one. Except pre I have multiple amps & sources.

 

[mpw]

i see a group buy cluster forming

 

[Ravindra Desai]

By the way Even Hyderabad is not far from Kolhapur , (I will try to meet you if possible, during my Next Belgaum Visit)

I just returned from Belgaum!
b.t.w. I worked with GE in Cyber Pearl in HiTech City from Sept. 2005 to June 2014. I liked the city. It is very visitor friendly.

Did try it in the morning, because I had to rerun audessey due to furniture adjustments , but Audessey is not accepting calibration without Front channels (Logically it makes sense). Will have to Connect Surrounds to Fronts on AVR , Set Surrounds to 'None', recalibrate and see (Postponed for Sunday hopefully)

I suggest that you kindly do not do anything that the user manual does not recommend. This applies to all who are involved in this exercise.

I was wondering if you could Just Make the Preamp version of your AR, So user gets the flexibility in deciding the amplification and Speaker signature of his choice, Just an optimistic thinking further, if you could incorporate the digital inputs and your version of digital Phono inputs into the Preamplifier (Rather - Pre processor to be specific) it will cater to requirements of many. Some People can use 3 Powered Speakers & Active subwoofers or 3 Channel Poweramp + Active Sub to get the desired effect. Best of Luck with your future endeavours

The preamp version of the DSP is a very good suggestion. Users already having an AVR can use the analgue EXT IN input to power all the 5 channels and the subwoofer from this DSP preamp signal. Cost and overhead of an additional power amps can be saved. Also you get to use your current speakers.

i see a group buy cluster forming

This thread belongs to @tuff .
Can any one of you start a separate thread about a Standalone Digital Audio Processor (DAP)? I'll reply what I have in my mind there?

Or, I'll just reply in the thread My Digital Audio Processor

Thanks!!

Regards

Ravindra.

 

[spirovious]

The preamp version of the DSP is a very good suggestion. Users already having an AVR can use the analgue EXT IN input to power all the 5 channels and the subwoofer from this DSP preamp signal. Cost and overhead of an additional power amps can be saved. Also you get to use your current speakers.

Most of new AVRs stoped providing 7.1 ext input other than marantz.That can be an issue.

 

[Ravindra Desai]

Or, I'll just reply in the thread My Digital Audio Processor

Kindly check for reply here: https://www.hifivision.com/threads/my-digital-audio-processor.69340/page-2#post-776405

Regards,

Ravindra.

 

[Hari Iyer]

Most of new AVRs stoped providing 7.1 ext input other than marantz.That can be an issue.

Mine is a vintage model from 2003 Denon AVR-1604 and still rocks

 

[dillihifi]

I also have a model with 7.1 analog ins so would like to embrace the philosophy of AR. It all depends on the price of the Preamp /DSP if at all the same is possible.
What I have gathered is that he is using pre-set cutoffs so using other speakers may not be optimal though I fail to understand why when you use a 2.1, perhaps the only issue is when using it in 2.0 where you would need the full range sound to be fed to the speakers.

I will be keeping close watch and if the pricing is reasonable will like to try it out for HT duties in a bedroom

 

[Ravindra Desai]

I also have a model with 7.1 analog ins so would like to embrace the philosophy of AR. It all depends on the price of the Preamp /DSP if at all the same is possible.
What I have gathered is that he is using pre-set cutoffs so using other speakers may not be optimal though I fail to understand why when you use a 2.1, perhaps the only issue is when using it in 2.0 where you would need the full range sound to be fed to the speakers.

I will be keeping close watch and if the pricing is reasonable will like to try it out for HT duties in a bedroom

Kindly check the thread here:
https://www.hifivision.com/threads/my-digital-audio-processor.69340/page-2#post-776405

Regards,

Ravindra.