Thread: 5.1 SACD Player

Posts: 32
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Post by Kal Rubinson January 30, 2010 (21 of 32)
armenian said:

Call me an idiot, but I must ask, what is “transmission line speaker?


Transmission line loading for woofers was very popular way back and does permit excellent bass extension for a given driver. I was a big fan of such designs. OTOH, having good bass extension in the main speakers does not, imho, obviate the need for subwoofers for several reasons.

First, specialized subwoofers can go lower with more power than the woofers in virtually all full-range loudspeakers. By analogy, I drive a station wagon so I can haul speakers and equipment that would not fit in a regular sedan but there is no question one could haul more in a truck.

Second, in consideration of room acoustics, rerouting the low bass to a subwoofer permits it to be placed (and equalized) for optimal bass response without compromising placement for imaging and other considerations. Conversely, main speaker placement is not compromised to accommodate low frequency response.


Post by jullepoika January 30, 2010 (22 of 32)
armenian said:

what is “transmission line speaker?

Woofer is placed in a box with open back. Not just normally open, but forming a fairly long tube with large enough cross section to allow bass waves to travel outside the box fairly unhindered. This tube has to be one half wavelength long at the lowest bass note which needs to be amplified by the contraption. For a 30 Hz note this would be 5 meters long. The idea is to sum the front signal with the reverse phase back signal, which is acoustically delayed to match the front signal in phase at the desired frequency where the front signal alone starts to slope down. To slow the speed of sound down this tube is filled with wool, thus the tube part can be made shorter and the box smaller. Wool also absorbs the higher frequences, only the desired low frequency is emited by the transmission line tube.

This trasmission line bass systems makes a very good system with good impuse response in the bass. The bad part is the exactness required in making the box, complicated and heavy construction, big size (compared to a bass reflex)and the not so exact science of packing the wool. Big, expencive, on two words.

Transmission lines were popular in the distant past. The modern theory for exact bass reflex calculations were introduced in the sixties and after that bass reflex boxes became so good that transmission lines fell out of favour. Also, at that time clean 40 Hz was good bass, now 20 Hz is needed, and making a loud 20 Hz capable transmission line speaker is unpractical, it would have to be huge, size of a car at least.

Post by Disbeliever January 30, 2010 (23 of 32)
armenian said:

Call me an idiot, but I must ask, what is “transmission line speaker?


Google PMC speakers . However they use foam interior whilst mine use Long hair Wool.
Dimensions Width 13" Height 45" Depth 18" they go down to 20Hz and can shake the room. NO SUB REQUIRED - Thank you.

Post by flyingdutchman January 30, 2010 (24 of 32)
WKRP said:

Therefore, "which is best" depends on which unit's D/A chip gives you the better sound. I bought one of the first Oppo BDP-83 players, which plays both SACD and DVD-A. I recently sent it into the shop to get the "BDP-83SE" upgrade. They upgrade the D/A chip, which affects the analog outs but not the digital HDMI outs. I have heard the SE uses a great chip, so I want my player doing the D/A conversion. I do not care what chip my receiver has, I only care that is has 5.1 analog inputs. Actually, the BDP-83 supports both 5.1/7.1 output.


How much did they charge? I have the same model and would like to upgrade.

Post by Kal Rubinson January 31, 2010 (25 of 32)
flyingdutchman said:


How much did they charge? I have the same model and would like to upgrade.

Why not go to the Oppo Digital website and look it up for yourself? Last I heard, there was a deadline for obtaining this upgrade.


Post by TheProf September 2, 2011 (26 of 32)
A transmission line speaker is basically a back to front horn. Imagine the speaker driver on the front as normal but the rear sound that comes out of the back of the bass speaker vents into a folded horn, or transmission line. This has the effect of resonating at very low frequency effectively increasing the output of the speaker at frequencies below 30Hz, or 30 cycles. Much energy is contained in classical music and organ music below 30 hz, and quite often right down to 15 or even 12 hz on Organs and bass drums, and some electronic music too.
Whilst no sub is required, a very good quality sub will go down much lower, as its often powered.

Post by Bobpaule November 24, 2012 (27 of 32)
Reviving an old thread, the Denon DVD-A1HDCI sports a fully dedicated isolated and balanced analog stereo XLR, and 7.1 RCA outs.

More importantly all powered by the exotic AKM DACs like in Esoterics.

While its BD abilities have been botched by the latest firmware it remains a stellar performer for SACD, complimented by the Lilliput 8" HDMI display near my seating position for easy ID3 referencing and saving lamp hours on the PJ.

Post by Bobpaule November 24, 2012 (28 of 32)
New McIntosh MVP891, even does BD 3D, looks like same DACs as in the new Oppos.
Rumor has it if you don't need BD 3D you get the MVP881.

Post by Bobpaule November 30, 2012 (29 of 32)
Last one, my research on XLR Stereo and RCA 5.1
sporting machines, along with the audioholics
reviews shed some light on the evolution of the clones:

1. DVD-A1UDCI (original)

2. UD9004 (copper adds extra 20 lbs)

3. MVP881 (steel and glass $$$)

4. MVP981 (3D)

Furthermore some 8-10k players are BDP-83SE knockoffs?

Hanging on to A1UDCI/PS3(Harmony IR) combo for the next
decade. Audyssey XT32 or not, i believe the fewer conversions
and corrections, the better the sound, Auralex panels and
anaechoic subs fix the rest, right?

Dya know that the BDP-105 has 2 DACs only, both below the
6 AKMs in the above machines?

Post by Fitzcaraldo215 November 30, 2012 (30 of 32)
Bobpaule said:

XT32 or not, i believe the fewer conversions
and corrections, the better the sound, Auralex panels and
anaechoic subs fix the rest, right?

If you are talking about a-d and d-a conversions, then I generally agree, they are to be avoided. But, some quality units do the a-d virtually transparently. So, I have heard systems where with vinyl, for example, they sound better with an a-d conversion plus Audyssey or similar EQ.

Most off the shelf passive room treatments do not touch the region much below 100Hz, though Kal has reviewed a few that do go below that in Stereophile. They were not panels, but active room mode cancellation devices or tuned resonators. But, I do not hold out much hope for Auralex panels in the deep bass. Panels need to be really huge to deal with bass frequencies and the very long wavelengths involved.

What is an anechoic sub? They can measure great in an anechoic chamber, as most do, but put them in a typical room and you are likely to get swings of up to +/- 10 dB or even more due to room modes. It is unavoidable without comprehensive treatments and/or EQ. That is just the nature of typical listening rooms and the laws of acoustics. It would be nice if corrections were not necessary, but it is wishful thinking to believe otherwise if optimal bass is your goal.

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