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A large 3 Way curved enclosure

Gahf

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Building a large 3 Way enclosure

Requirement: 3 way speaker active/passive speaker compared against my benchmark reference 4 way active system which scored a perfect 10 with listeners.
Subjective requirement: A speaker which could emotionally move the listener, as several people who auditioned the 4 way speakers did say they could feel the music and raise emotion levels.

Here is the picture of the 4 way speaker system running active with 8 channels of amplifiers, using two 4 way active crossovers crossed at 140hz, 450hz, and 3.3khz. There are separate enclosures for the sub woofers and the rest of the 3 way. The subwoofers are 4* 8 inches ported with the port tuned at 26hz, and are generally capable of shaking the floor and can quite easily reproduce the deepest growl in movies which you can feel. The rest of the 3 speakers cover the spectrum from 140hz-20khz with a fairly flat line. The crossovers are entry level analogue, and I generally need to reduce the slope of the mid/tweeter for old songs, and with minor adjustments they sound fantastic across all genres of music. So once these speakers were made after several months of fine tuning the enclosures and matching the speakers, this quickly became the benchmark. So I have been trying for the past several months to build a slightly smaller version with a higher family acceptance factor which one might be happy to install in the living room or a dedicated listening room, but which would come close to the quality of these benchmark speakers. I will perhaps open another thread posting pictures and specifications or maybe post it later in this one, but this thread is about the 3 way speakers.

So here goes. IMG_1262.JPG
 
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Gahf

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Here is a mug shot of the 3 way speakers currently running active. Once the crossover points and slopes, etc are measured, these will be dismantled and finished in a high gloss veneer polish. Please ignore the quality of the photo at this moment, will post cleaners pictures as we progress in this post. IMG_1338.JPG
 
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Gahf

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The dimensions are 12*54*23 (rounded off to the nearest inches), and each side has a complete peerless set of 4 6.5 inches woofers, two 5.5 inches used as midrange in a classic mtm separate enclosure. The speakers are undergoing tuning as I write this post and fairly soon I shall be able to publish the final frequency graph. At the moment they are just a shade over 100 db and initial reports are very favourable to the tone of the music. I think this would need a baffle separation for the woofers and the mtm, as there are a few dips around crossover points, so some work needs to be done yet.

The walls are curved with the back being just 6 inches. After the initial 19 mm curved wall, there is a 4mm ply for smoothing the walls and providing some sort of a sandwiched layer, and then covered with a further 4 mm mahogany high quality veneer. Currently the first three rounds of polish has been completed with a dark stain, and the baffle is 1.5 inches cnc cut and painted black in automotive paint with the usual surfacer, putty combination. Once these are tested in this enclosure, they will undergo the final 4 rounds of polish, chrome and steel legs, double coats black paint on the front baffle, and a switchable active to passive 6 binding posts at the back. Here are some pictures of these speakers as they were being built.

They are really heavy, around 120 kgs each owing to the double front baffle, almost double walls, and several kgs of glue to hold the individual strips of the walls together. IMG_1313.JPGIMG_1314.JPGIMG_1315.JPGIMG_1316.JPGIMG_1317.JPGIMG_1320.JPGIMG_1322.JPGIMG_1330.JPG
 

Tangband

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Very nice looking speakers .:)
Do you have a filosophy how to move the emotions of the listener ? Low distortion drivers such as yours in big boxes will help a lot, allowing high spl.

Here are some more other suggestions you might try, If you want to.
One such thing could be stereosystem compensation +1,5 dB Q=3 at 1.5 kHz, and - 1,5 dB at 3,5 kHz and +1,5 dB at 6,5 KHz .
When I made the HYBRID that was a dsp 3-way active speaker with waveguide and good directivity I tried some of those frequency response tricks. This made the sound from the stereo setup more 3- dimensional. Another trick is to glue bitumen on only one side of the loudspeaker cabinets avoiding any tune-fork effect from the cabinets resonanses. Different sorts of feets or spikes below the speaker also changes the perceived sound quality slightly.

Another trick might be to allow some coloration in the source or preamp/dac .

Loudspeaker setup in the room using tunemethod ( listening to the clearest bass tunes while moving the two speakers to the best position in the room - ie where they sound less boomy ) is in my opinion a good way to perceive the most of the emotions from the musicians intensions on the recording, when listening.
 
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Gahf

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Very nice looking speakers .:)
Do you have a filosophy how to move the emotions of the listener ? Low distortion drivers such as yours in big boxes will help a lot, allowing high spl.

Here are some more other suggestions you might try, If you want to.
One such thing could be stereosystem compensation +1,5 dB Q=3 at 1.5 kHz, and - 1,5 dB at 3,5 kHz and +1,5 dB at 6,5 KHz .
When I made the HYBRID that was a dsp 3-way active speaker with waveguide and good directivity I tried some of those frequency response tricks. This made the sound from the stereo setup more 3- dimensional. Another trick is to glue bitumen on only one side of the loudspeaker cabinets avoiding any tune-fork effect from the cabinets resonanses. Different sorts of feets or spikes below the speaker also changes the perceived sound quality slightly.

Another trick might be to allow some coloration in the source or preamp/dac .

Loudspeaker setup in the room using tunemethod ( listening to the clearest bass tunes while moving the two speakers to the best position in the room - ie where they sound less boomy ) is in my opinion a good way to perceive the most of the emotions from the musicians intensions on the recording, when listening.
Thank you. All suggestions very valuable. Have tried one or two myself but will action the rest and update you of progress.

I am blessed to have two very capable listeners in my office. About a year and half ago I wondered if I could try my hands in building high quality speakers and have been trying to develop a range of speakers since then. Actually the bug bit me when I went shopping for an accomplished system for my home setup and after buying the regular Bose and Marantz and Denon and Yamaha found out if I wanted better they cost a bomb.

A couple of months ago I managed to build a 4 way which really moved these listeners. Since then I have invited several to audition these and some have said that these speakers move them emotionally after they listen for a while. I have myself found going into a reverie listening to them. So my philosophy or call it whatever is whatever moves a variety of people. An audio engineer who has measured them played some audiophile tracks and was astonished that they covered the spectrum quite easily. They also measure well though I have found as you have rightly said some coloration beyond what the REW mandates is sometimes desirable.
IMG_1262.JPG


Agreed, big heavily damped and enforced boxes with diffusers inside and sometimes more than one layer and multiple drivers run actively do create a very pleasing soundstage. Here is a photo of the speakers I am talking about.
 

morpheusX

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I will perhaps open another thread posting pictures and specifications

Please do!
I would love all the details you can provide, specifically how have you managed to measure the drivers, crossover selection, etc :)
 
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Gahf

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Please do!
I would love all the details you can provide, specifically how have you managed to measure the drivers, crossover selection, etc :)
Absolutely will write. This one took me several months of speculation plus hit and trial even after simulating box designs and driver responses. Then I decided to do separate units, one for the sub woofer for coverage upto 100 hz, and the next above 100hz, but placed in a single line for a large radiating area. I experimented with Peerless sls 10 inches and dayton audio 8 inches with a height between 40 inches to 54 inches, and depth from 18 inches to 23 inches (somehow trying to calculate what would work with 4 drivers each side) and the response remained elusive. Then I took out 8 8 inches drivers which were lurking in a corner which I had got a local manufacturer in Delhi to build for me for use as individual subwoofers, did a double wall 48*18 inches box with plenty of braces and it worked! Each of these drivers needed around 1.15 cuft and to my delight this worked.

I had in the meantime built a few three way boxes with responses from 100 hz- the one you see in the picture uses a Celestion pro 8 inches FTR driver with a wonderful flat measurement from 100-3k hz, and I used it for 100-450 hz with a peerless silk dome 1" tweeter to take over from 3.3khz onwards. The mid range from 450-3.3khz was covered with a 6 inches carbon membrane woofer (I think a China import).

I am running these active with 2 DBX 234 analogue crossovers each working mono 4 way, with an 8 channel amp (600 watts, 200 watts, 200 watts and 100 watts) class AB with just 3 stages and limited negative feedback. Perhaps these amplifiers would not stand the test of distortion measurement, but this entire setup gets the work done beautifully. Two of my friends who have showrooms of audio equipment are convinced this sounds better than products of quite higher overall value.
 
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