The Darbari: new speaker project

[tcpip]

Tried doing nearfield measurements of midrange and woofer, since it will be nice to have at least some idea how they behave in the lower regions. I thought this data may help me do a crossover at 150Hz or thereabouts more intelligently.

So, I took multiple readings of each driver and this is what I got. This is the midrange graphs:

And this is what I got for the woofer:

All these graphs have been smoothed 1/16 octave. I know that for room correction, people seem to use 1/3-octave or 1/4-octave smoothing. But I am trying to keep the smoothing to a minimum to get a feel of the data -- I don't know what is 'right" for low-frequency crossover design. Never done a 3-way before.

Are these graphs supposed to have so much spikes and troughs?

 

[tcpip]

Fixed the nearfield measurement problems. Got a crossover done "on paper" (i.e. in the modelling software), then programmed it into the MiniDSP.

Realised that I had forgotten baffle step compensation. Added 4 dB of that. Gentle rise below 300 Hz, shelving out at 150 Hz.

Did some tests with woofer power, and realised that my 10-inch woofer can generate only so much low freq and no more before it bottoms out. So, I decided to live with the SPL levels I can get. The sound is very clean.

Realised that my 6-channel AVR (well, 6.1 channels actually, which means 6 channels of power amplification) has some problems with its controls, so temporarily rigged a 5.1 channel AVR and a 2-channel stereo power amp with their gains set carefully to identical levels. So, I now have six channels of power amps.

Finally, last night, wired up the last tweeter, and got the rig to work. One can listen to music now.

When are you guys coming home for a listen? I am game for any weekday evening or weekend, late nights are good too.

 

[GeorgeO]

Sirji

I would have come over to audition your man toys in a heartbeat if I was in the neighbourhood!

George

 

[mpw]

tcpip,

are your speakers completed ?

or will my ears be the guineas ??

i would like to drop in on a weekend afternoon.

mpw

 

[tcpip]

tcpip,

are your speakers completed ?

or will my ears be the guineas ??

i would like to drop in on a weekend afternoon.

mpw

Really sorry to respond now -- I have been a bit tied up and was out of the country for a week.

As far as my ears are competent to judge, I think the Darbari are ready. See some of my impressions here: Darbari part 7: the sound | dhandanought.org | tcpip

Will love to have you drop in. When?

 

[tcpip]

I would have come over to audition your man toys in a heartbeat if I was in the neighbourhood!

Sir, you are one of the motive forces who have encouraged me to go for the kill and build something this ambitious. You have to be in the neighbourhood. Keep half a day aside on your next Bombay trip.

 

[Hari Iyer]

When are you guys coming home for a listen? I am game for any weekday evening or weekend, late nights are good too.

@tcpip
Great thought process and design effort gone in designing the darbari speakers.

I will definetly like to come down for the listen. Please suggest suitable date and time on weekday / weekend next week.

Cheers,

 

[Hari Iyer]

Re: Drivers are being fitted

Driver fitting has started.


A tragedy occurred. In spite of having built a few speakers, and having spoilt a few drivers, I spoilt one of the tweeters today. it's the same old problem -- tweeters are unable to withstand the heat of the soldering. One of the leads of one of the tweeters came clean off. I have ordered a replacement from the US, through Borderlinx. I will waste Rs.8-10K now.

I have moved to using QC jacks (female QC interconnects) to push-fit the cable onto the driver terminals. I have crimp-type silver-plated female QC jacks of all three sizes, so I can fit cables to any driver this way. This minimises the soldering needed. (I adopted this practice after having lost 1-2 tweeters.) Even after using QC jacks, you still need to solder a little bit to ensure a solid and reliable connection between the QC jack and the terminal "tongue" (the male QC jack) of the driver.

Even a three-second touch with the soldering iron softens this tweeter's plastic base for the lead. With the first tweeter, I had to struggle a bit longer, and the base clean melted and broke off. Really pissing-off and irritating, and makes me feel like such a ham-handed amateur.

In future, I will coat the plastic base block of each lead in a blob of Araldite, so that the block becomes strong and does not soften with heat. Am sick of losing lovely, expensive drivers.

The mounting screws are lovely, aren't they? They are these items from TheAudioCrafts. I am so thrilled with their looks that I intend to use them for all future projects. Unfortunately, they are not available in longer lengths, e.g. 45mm or longer, which would have been required for large heavy woofers. The photos are quite sharp; view them in full size to see the screws.

The rear view shows the binding posts. These are Dayton Audio binding posts from Parts Express with their matching mounting plates also from Dayton Audio.

I always clean and strip gold /tin coating in the leads of the woofer and tweeters for atleast 10 to 15 minutes before soldering. Apply solder first to the tweeter leads. Also strip and clean the wires and apply solder then to the wires. You can then directly solder the wire to the tweeter terminal in just 1 to 2 seconds. I must have soldered more than 200 woofers and tweeters with this method taught to me by my elder brother and till date have not ruined a single driver.

 

[tcpip]

@tcpip
I will definetly like to come down for the listen. Please suggest suitable date and time on weekday / weekend next week.

Will you be okay with Wednesday 10 Dec evening?

If you prefer weekends, I am afraid I will be out during the 13-14-Dec weekend, and you're most welcome to come on Sun 21 Dec afternoon if you're free?

 

[tcpip]

Finalized on the finish as yet? Veneer polish? Shades .. cherry or walnut? Its turning out to be nothing short of a classic! :licklips:

How about following up on those nice words of Jan 2014 with a visit in Dec? Will love to have a few of you friends come over for a listening session. Bring your own CDs. (Sorry, no vinyl -- I don't have a turntable.)

 

[tcpip]

Re: Drivers are being fitted

I always clean and strip gold /tin coating in the leads of the woofer and tweeters for atleast 10 to 15 minutes before soldering. Apply solder first to the tweeter leads. Also strip and clean the wires and apply solder then to the wires. You can then directly solder the wire to the tweeter terminal in just 1 to 2 seconds. I must have soldered more than 200 woofers and tweeters with this method taught to me by my elder brother and till date have not ruined a single driver.

So, this means that you don't use QC clips, right?

How do you ensure that the wires stay in place on the leads when the solder cools? Do you twist the wires into/around the terminals of the driver?

 

[tcpip]

Please, anyone wanting to drop in for a listen, most welcome. Please feel free to get your own CDs, or any digital media files on a USB stick. I have a media player which plays pretty much any audio media which I have thrown at it. And I have a CD player (an old Sony DVD player which was built to showcase SACD and high-end audio capabilities) which can play SACD. So, feel free to get your favourite SACDs.

 

[Hari Iyer]

Re: Drivers are being fitted

So, this means that you don't use QC clips, right?

How do you ensure that the wires stay in place on the leads when the solder cools? Do you twist the wires into/around the terminals of the driver?

No, I dont use QC clips as over time this may tend to offer serious contact resistance.

Speaker manufacturers usually coat the driver terminals with a coating of silver tin to prevent corrosion of the terminals which usually is copper. Hence before soldering the tin coat needs to be removed so that soldering becomes more easy.
Same with the wire, most wires may get oxidized due to moisture and the wires also needs to be removed of the corrosion and then twisted and should be first given a layer of solder.

This process ensures that both the driver terminal and the wire has same material (solder) to be joint. Then when you solder the wire on the driver terminal you do not have to wait for longer than 2 to 3 seconds for the joint to be secure. This way i can hold the wire with my hand and do not require any special tools to do so. Only holding the wire by hand for more than 10 sec make your finger prone to burns.
Please try this method next time and let me know how you find it.
Cheers,

 

[tcpip]

Re: Drivers are being fitted

No, I dont use QC clips as over time this may tend to offer serious contact resistance.

I was trying out the approach of using QC clips and then soldering them to the terminals. I thought this would obviate the need to twist the (sometimes quite thick) wires onto the terminal -- this twisting adds physical stress to the (sometimes delicate) terminal.

I will try the pre-tinning and soldering approach you suggest.

 

[Hari Iyer]

After an extended wait of almost 5 years, i finally got to listen the Darbari speakers last week Saturday evening. It was a perfect environment to listen music as it was raining and most of the day and there was nothing else to do in the evening other than watching TV. (BTW, i got installed a MI 49" TV at my in-laws the same day afternoon. Not happy with the PQ though).

When i reached Tarun's apartment i was greeted by Tango which looked ferocious initially but later realized that he was very friendly and nice. When i entered the listening spot, i was amazed by the size (height, width and depth) of the Darbari speakers and wondered how Tarun could convince others in the home for such a monster. Not that i had not build such huge box before but that was 25 years ago before i got married. The Darbari required a huge box because it was using a 10" Dayton woofer which was in a sealed box loading. To get tight low end and extension the box needs to be larger than normal to do justice. The mids were 6" Dayon from the same Reference family. The tweeter however was a Peerless 1" silk dome.

This is the second time i have ever listened to a active setup. The first time i listened was at Genelec showroom at Mahim and i was not impressed with that outcome. That gave me a feeling that if a brand like Genelec could not do good with actives let alone Diyers. But that analogy ends there because the Darbari is a active setup with lots of muscle. It uses a miniDSP in the chain which has been meticulously tuned and optimized by Tarun after countless measurement and simulations. The output of the miniDSP feeds the 6 individual channels of the Marantz AVR. The source was from a MAC hard drive + Raspberry PI. Tarun does not have any pure analog source like me (Tape deck or TT), so to get a flavor of how analogue will sound is not possible.

We initially listened to slow country music and later switched to Hindustani classical music from Tarun's selection and found the vocals to be spot-on with clear tonality and body. The sound stage was well spaced and the center image was dead center. The overall balance of the sound was quite good, coherent and gave the impression of a single driver being played. This was all in the near field listening at the ideal sweet spot which is around 4 to 5 feet from the speakers. The speakers will be at a distance of around 5 to 6 feet away from each other and around 2 feet from the front wall. There was lot of space behind me as i was in mid field listening position. The lows were quite tight and deep and was very well blended with the mids and highs. This speakers are excellent for listening to classical music, Ghazals, Jazz type of music and almost any genre thrown upon them . I later moved away from the sweet spot and wanted to see how they sounded off-center and some of the coherence got muffled which is obvious as its not easy to get the entire room as your sweet spot but it still managed to be well integrated.

I later played a high resolution fast pace music with lot of violin and the Darbari was not able to keep pace with its resolution. This imo would not be because of the speaker themselves but because of the amplifier dynamic range extension which could not keep pace with the transient and got blurred. Also i later realized that the Darbari uses a stock polycab + finolex wires as speaker cable. I had 4 months ago used similar polycab wires as speaker cable when i accidentally discovered that this cable robs the speakers of music. The polycab in my setup made the sound very fatigue prone and made everything sound similar with no distinction of space and tone. If Tarun takes my suggestion the first level of modification will only be the speaker cables and nothing else. In my case the polycab got replaced with a multi-strand silver plated copper wire of 3 different SWG (22, 20,18) twisted in golden ratio cross-section. I am now happy with this combination and this won't break his bank.

Later our conversation was about the generic diy scenario and the pros and cons of building speakers which we both had similar views. Also i got to see his upcoming project where he plans to use a passive crossover with the Satori speakers. I will be following this build for sure. All an all an evening well spend learning from Tarun about active crossover design methods, large sealed enclosure capabilities, mid-field listening experience and a lot more. I have also invited Tarun when time permits for listening my OB speakers as it has a completely different approach. Hope that happens sooner or later.

 

[tcpip]

After an extended wait of almost 5 years, i finally got to listen the Darbari speakers last week Saturday evening. It was a perfect environment to listen music....

Thanks for finally taking the trouble to come over, Hari. It was a very pleasant two hours...

For those who are curious about the Ferocious Tango, here are two photos:

I have never fallen in love with a woofer the way I have with Tango.

I have a feeling that Hari has been astute about commenting about my amplification. On the one hand, these speakers are the most resolving that I've heard, and on the other hand, the amps are about as bad as mainstream branded amps can be. Since I've found another home for the Darbari, I will have no need for this amp any more, and I'm arranging for some really excellent amps (DIY, what else) to rival what the non-DIY FMs call "high end" boutique branded amps, for my future experimentation and listening. One KVA toroidal transformer has been ordered from Torotrans...

I have an analog source Hari -- a really top quality Aiwa deck which has 3 separate heads and support for Dolby B/C/S/HXPro. I also have some amazingly good metal cassettes recorded by someone on a good Nakamichi deck. We didn't have time to bring those things out to the living room and hook them up. Next time...

 

[tcpip]

This imo would not be because of the speaker themselves but because of the amplifier dynamic range extension which could not keep pace with the transient and got blurred. Also i later realized that the Darbari uses a stock polycab + finolex wires as speaker cable. I had 4 months ago used similar polycab wires as speaker cable when i accidentally discovered that this cable robs the speakers of music. The polycab in my setup made the sound very fatigue prone and made everything sound similar with no distinction of space and tone. If Tarun takes my suggestion the first level of modification will only be the speaker cables and nothing else. In my case the polycab got replaced with a multi-strand silver plated copper wire of 3 different SWG (22, 20,18) twisted in golden ratio cross-section. I am now happy with this combination and this won't break his bank.

Sir, I just wanted to point out that my current speaker cables are no ordinary cables -- they are Sexy (TM) speaker cables. See here for full details.

Quoting the last section of my page on my cables:

 

[prem]

tcpip, the woof in your place must be the most real sounding

 

[Deleted member 15865]

For those who are curious about the Ferocious Tango, here are two photos:

I have never fallen in love with a woofer the way I have with Tango.

Those eyes speak!

 

[Hari Iyer]

Sir, I just wanted to point out that my current speaker cables are no ordinary cables -- they are Sexy (TM) speaker cables. See here for full details.

Quoting the last section of my page on my cables:

Tarun, I had exactly similar views about polycab untill I discovered the multi-strand silver plated copper wire. In fact I remember arguing with FM @ Bhagwan when he asked me to replace my Polycab with Belden year and half ago. Argument was on the impedance and capacitance of both Belden and polycab being same. The similarities ends there I believe. Polycab as speaker cables are now history for me