Multi-Channel, Multi-Amplifier Audio System Using Software Crossover and Multichannel-DAC

[dualazmak]

A new series of audio experiments on reflective wide-3D dispersion of super-tweeter sound using random-surface hard-heavy material: Part-2_ Comparison of catalogue specifications of metal horn super-tweeter (ST) FOSTEX T925A and YAMAHA Beryllium dome tweeter (TW) JA-0513; start of intensive listening sessions with wide-3D reflective dispersion of ST sound

Hello friends,

Today, I could manage preparation of comparative representation on catalogue specifications of metal horn super-tweeter (ST) FOSTEX T925A and YAMAHA Beryllium dome tweeter (TW) JA-0513 as shown in this Fig.18.

As I described in my Part-1 post #911, in my audio setup, the Fq coverages with TW JA-0513 and and ST T925A are well overlapped (they sing together); JA-0513 has ordinary efficiency with good directivity characteristics, while ST T925A has very high efficiency but narrow directivity (typical for metal horn super-tweeters) as you can see in above Fig.18.

I assume (or even believe) this comparative representation in Fig.18 would reasonably explain the favorable contribution of the reflective wide-dispersion ST sound to (slightly) better 3D sound stage/image as well as to wider/larger sweet spot/sphere around my listening position; by the sound dispersion, the directivity of ST sound would become similar to TW, and the possible slight gain-loss of ST sound can be quite easily compensated by the amplifier YAMAHA A-301 directly dedicatedly driving STs.


In any way, today I also started my intensive listening sessions testing/comparing the four reflective dispersion configurations for ST T925A where I use the my default Case-0 (no reflectors) setting as reference sound.

Today, I intensively listened to track-001 through track-005, all of them are full orchestral music, of my consistent "Audio Sampler/Reference Music Playlist" (ref. here #670, #588 (including YouTube links), and this dedicated thread) using the Case-0 through Case-4 settings;

I found again, similar to the preliminary result of yesterday, that Case-2 setting (i.e. reverse straight reflective dispersion), "most preferably among the four dispersion settings" gave better 3D sound stage/image as well as wider/larger sweet spot/sphere around my listening position for the full orchestral music we tested/evaluated (my wife partly participated).

Yes, very interestingly Case-2 setting is so far so nice...

You would please note that the crystal-glass reflector of random multiple reflection surfaces/pattern is placed slightly in slant, I mean slightly face upward. This is intending to minimize the reflected sound would go again into the cavity of the ST T925A.

I will slowly and steadily continue our intensive comparative listening sessions during coming several months using my "Audio Sampler/Reference Music Playlist" (ref. #670 and this dedicated thread).

 

[j_j]

OK, thank you for the information.
At least I myself do stick to, however, safe and (almost completely) transparent rather affordable 10 microF capacitors to protect my tweeters and super-tweeters.

Yes, in fact, we use 100 mF cap with a parallel .1 UF silver mica on ours. Zero voltage across it in normal operation (well, under microvolts at least). Yes, we know how to measure.

 

[j_j]

And it's more reliable, because it's passive. SSR's can introduce some nonlinearities as well.

They commonly cause center-clipping. I would never put a solid-state relay using semiconductors as the "contacts" EVER in a signal chain. NEVER.

 

[mhardy6647]

DON'T! If you mention his name, he appears!!!

I think one has to say it three times -- like Beetlejuice.

 

[dualazmak]

Just for your possible interest and reference...

Partly relating to my current "new series of audio experiments", I just wrote my post #637 on the remote thread "Classical ♫ Music only | Some you listen now or recently, some you love...".

 

[dualazmak]

A new series of audio experiments on reflective wide-3D dispersion of super-tweeter sound using random-surface hard-heavy material: Part-3_ Listening evaluation of sound stage (sound image) using excellent-recording-quality lute duet tracks

Hello friends,

As I have shared in my post #642 and in many of my posts on another thread “Lute Music and Other Early Music: Stunning Recordings We Love”, lute music tracks of excellent recording quality are always nice challenge to our audio system.

As a part of my present series of audio experiments, today I intensively listened to this wonderful excellent-recording-quality lute duet album especially tracks 1 – 4, Sylvius Leopold WEISS: Sonata in C Major by Edward MARTIN and Paul BERGET; I download-purchased the album at MAGNATUNE site in 2004. Of course, all the SP drivers were singing together having the total Fq-SPL at listening position shown in Fig.14 and Fig.15 in my Part-1 post #911.

Even though the sound quality of the clips would not be optimal, you can hear/listen to the four tracks on YouTube; I highly recommend you to download-purchase the entire album if you would prefer and if you would be interested in this kind of music which are very much suitable for checking reproduction of not only total S/N but also sound stage/image.

Spoiler

Track-1: Andante

Track-2: Allegro I/II

Track-3: Largo

Track-4: Tempo de Minuetto

I usually listen to this download-purchased album with relative +2.7 dB boost in L-channel by DSP-EKIO’s input panel for my preferable L-R balance for the album; I do not know this can be attributable (or not) to either of, or any combination of, these factors:

1. Asymmetry of my listening room furniture and acoustics,
2. Slight off-center alignment of microphone at the recording venue,
3. Slight difference in distances of the two lutenists from the microphone,
4. Difference in personal “gain” preferences of the two lutenists,
5. Essential difference between the two lute instruments,
6. Acoustic asymmetry of the recording venue.

In any way, at least for us (with my wife) +2.7 dB boost in L-channel gives our best L-R balance and very nice allocation of the two lutenists; one lutenist sits at middle of left-to-center, another lutenist sits at middle of center-to-right, both between the L&R speaker system; of course the total hall/recording-venue sound for two lutes are very fantastic and enjoyable.

During the comparative listening session on the four (4) top tracks of this album, I set about +3 dB higher gain using the YAMAHA A-S301 integrated amplifier compared to my standard gain for super-tweeter (ST) sound (with no effect on upstream DSP XO/EQ/Delay/Gain/Phase configuration), since this +3 dB boost in analog domain would very nicely compensate the possible slight gain loss by the wide-3D reflective dispersion of ST sound.

We intensively listened to through the four (4) tracks five times with the Case-0 (no reflector) setting and with Case-1 to Case-4 setting with the glass reflector in front of STs T-925A;

For checking the “sweet spot / sweet sphere”, we rotated our heads and we actually 3D-moved around the center of my usual listening position (3.2 m away from the SP system).

I should not write too much here about differences of our subjective impression/sensation between the five settings, but I would like to share which setting among the five gave the best total sound reproduction in terms of stable/robust lutenists allocation (sound stage/image) as well as the widest/largest sweet spot/sphere around the center of listening position.

As the results of our intensive subjective listening sessions, we were very much amazed and impressed (again!) by the Case-2 reverse-straight wide-3D dispersion setting for STs gave considerably better/best stable sound stage/image as well as widest/largest sweet spot/sphere around the center of listening position. I can find no suitable wording to describe the wonderful sonority and excellent sound stage (sound image) given by the Case-2 setting which remained almost unchanged even if we considerably moved around; just amazingly nice…

After finishing today’s listening sessions, we (myself and my wife) unanimously agreed that for our further listening evaluations in this new series of audio experiments, we may reasonably exclude the Case-1 (straight against reflector towards us), Case-3 (reverse 45-deg toe-in) and Case-4 (reverse 45-deg toe-out) settings, and we would be better to mainly just compare Case-0 (no reflector) to Case-2 (reverse straight 3D reflective dispersion).

During the coming one month or two, I will slowly and steadily continue our intensive comparative listening sessions using my "Audio Sampler/Reference Music Playlist" (ref. #670 and this dedicated thread) as well as hopefully some other tracks and/or album of my interests; please be reminded, however, that I will share the results less frequently since they would be almost subjective evaluations.

I hope I would share (provisional) conclusion of this series of new audio experiments in my audio system in my acoustic environment by my next possible Part-4 post on this subject to be written within coming two months.

Edit on May 10, 2024:
I assume the below schematic drawing Fig.19 would assist your further understandings of my point on "sound image" in this post;

The excellent "sound image", i.e. sound allocation of two lutenists, remains unchanged even if we considerably move 3D around the center of my usual listening position (3.2 m away from the surface of the SP system). The wide/large sweet spot (sweet sphere) around the listening position is nicely reinforced/improved by the wide-3D reflective dispersion of the HF sound of super-tweeters which sing together with upper tweeters.

 

[dualazmak]

A new series of audio experiments on reflective wide-3D dispersion of super-tweeter sound using random-surface hard-heavy material: Part-3.1_ Listening evaluation of sound stage (sound image) using excellent-recording-quality jazz trio album

Hello friends,

As a part of my present series of audio experiments, today I intensively listened to this wonderful excellent-recording-quality jazz trio album "BLUE PRELUDE" by Karel Boehlee Trio; CD MYCJ-30358 M&I JAZZ. Of course, all the SP drivers were singing together having the total Fq-SPL at listening position shown in Fig.14 and Fig.15 in my Part-1 post #911.

Even though the sound quality would not be optimal, you can hear this album on YouTube;
https://www.youtube.com/playlist?list=OLAK5uy_lq7Nc4gqBIcXQLLsMy24AYYgpmngdmDfw

Here, let me refer to only one of the YouTube album clips; track-4 "High Times":

I have also touched on this track as one of my "Reference/Sampler Music Tracks" in my post #640 showing the Fq-Gain-time color spectrum of the track analyzed by Adobe Audition 3.0.1.

Furthermore, I use this track for sharing the video of dancing DIY 12-VU-Meter Array in my post #753.

Spoiler

The recording sound quality of entire album is really excellent (and very much enjoyable performance, of course!) really suitable for checking our audio system and room acoustics. By listening to this album with my audio system, I can easily understand the intentions of recording/mixing engineer(s) for sound image (sound stage) reproduction given by the CD release.

The drum set (drums and cymbals) is allocated in left-to-center, bass (contrabass) in center, and the main piano sound is allocated/spreaded in front center-to-right. It is interesting to note that, in piano sound, the lower keys are in center-oriented position and the higher keys are in right-oriented position. (Edited and corrected this paragraph on May 10 at 11:41 Japan Time.)

I assume this schematic drawing Fig.20 would assist your further understandings of my point on "sound image" in this post;

This time, as the objective of my present new series of audio experiments, I intensively and cafarfully tested/evaluated only the Case-2 setting, i.e. the wide-3D reverse-reflective dispersion of super-tweeter (ST) FOSTEX T925A HF (high frequency) sound by the random cut-glass surface of thick-heavy Bohemian glass bowl. Please again be reminded that STs FOSTEX T925A sing together with the upper tweeters (ref. Fig.13, Fig.14, Fig.15 in my Part-1 post #912).

In comparison to the reference setting of Case-0 (not reflector) (ref. Fig.06 in my Part-1 post #912), the Case-2 setting gave better stable and robust "sound image" schematically shown in the above Fig.20 as well as wider/larger "sweet spot/sphere" around the listening position (3.2 m away from the surface of the SP units, ref. Fig.02 of post #912) even if we considerably move 3D around the center of my usual listening position.

Again, the wide/large sweet spot (sweet sphere) around the listening position is nicely reinforced/improved by the Case-2 wide-3D reflective dispersion of the HF sound of super-tweeters which sing together with upper tweeters.

Edit on May 9, 2024 at 19:55 Japan Time
Just for your possible interest, both of the CD albums "LOVE DANCE" (MYCJ-30477 M&I JAZZ, 2008) and "SECRET LIFE" (MYCJ-30561 M&I JAZZ, 2010) by Karel Boehlee Trio have the similar reproduction of "sound stage/image" which I described above for the album "BLUE PRELUDE"; as I shared in my post here, these CDs has slightly better total sound quality (or slightly better "sonority", I may say). I am just now listening to these albums with Case-2 wide-3D reflective dispersion of super-tweeter (ST) FOSTEX T925A HF (high frequency) sound.
You can find several tracks of these albums on YouTube, even though the sound quality of YouTube clips would not be optimal.

Spoiler: Just two links to YouTube clips from album "LOVE DANCE"

 

[dualazmak]

I edited and corrected one paragraph in the above post #927:
The corrected paragraph is;
The drum set (drums and cymbals) is allocated in left-to-center, bass (contrabass) in center, and the main piano sound is allocated/spreaded in front center-to-right. It is interesting to note that, in piano sound, the lower keys are in center-oriented position and the higher keys are in right-oriented position.

The Fig.20 is correct from the beginning when I prepared/drew.