Carver Amazing Platinum Mark IV ribbon dipole 2-way. 4x12" woofers per speaker, 5' ribbon.

skid00

Member
Thread Starter
Joined
Mar 20, 2020
Messages
119
More  
Main Amp
2 x Adcom GFA 555
Front Speakers
Carver Amazing Platinum Mark IV
John Mulcahy - thank you so much for giving the world REW!

I've been spending a lot of enjoyable hours fixing my very old Carver Amazings' response. I haven't been able to find much documentation on these huge beasts (135 pounds, 4 feet wide, 5 feet tall, and about a foot deep). They are basically a 4x5' 3/4 inch sheet of plywood, with a 5' dipole ribbon and 4 x 12" dipole woofers. I bought them used, sight unseen, and upgraded them to the latest hardware available 28 years ago. They replaced a pair of Martin Logan Sequel II's, which sounded awful in my peak ceiling great room.

I've been amazed (sorry) with the deep, powerful bass, and am now thrilled with the extra 1/2 octave REW opened up for me. I run each speaker with an Adcom GFA555 200-watt amp. I *had* been running the amps strapped (800 watts), but had read that that destroys the damping factor. Two hundred watts is more than enough for my listening, even when pumping 'Bass I love you' through them. The Adcoms have overload lights, which have not blinked at 90+ dB. I don't dare push them harder, there are no replacement parts available, and I had a ribbon magnet tear part way thru a ribbon. I lucked out by using a silver conduction pen to repair the tear, but don't know how that will handle the ? 200 Hz and up frequencies supplied to the ribbons.

I've been comparing these speakers with online MDATs, and for the most part, they seem to be doing well to my hobbyist eyes... The waterfall plots show the untreated room reflections, and what I assume is the rear output reflected from the back wall. I have put the speakers into a room null (using the 'Room Mode Calculator' spreadsheet, and together with EQ, have eliminated most of the huge amount of bass at the room boundaries. At the listening position, the whole range (well, what my old ears can still hear - 16.5 kHz right and 8.5 kHz left) sounds present and equal.

I'd love feedback on these results. I wonder if I need to worry about the phase plots, and is the pre-ringing a problem? I used 'The Sheffield Track/Drum ' record to try to hear this, but the drum edge and other percussives sounded sharp and clear...











 

jtalden

Senior Member
Joined
May 22, 2017
Messages
887
Location
Arizona, USA
More  
Preamp, Processor or Receiver
Marantz AV7705 Pre/Pro
Main Amp
VTV 6 chnl NC252MP P-amp x 2
Additional Amp
Behringer DCX2496 x 2
Universal / Blu-ray / CD Player
OPPO BDP-103 Universal Player
Front Speakers
DIY SEAS H1456/H1212 Spkr x 5
Subwoofers
DIY JBL 2235H 15" SW x 2
Video Display Device
JVC DLA-X790R
Screen
Da-Lite Da-Snap 39105V - 92"
I wonder if I need to worry about the phase plots, and is the pre-ringing a problem?
These result are very good indeed. I wish I could hear this setup.
The phase rotation is just as expected for an ideal 200 Hz IIR XO and there is no indication of any delay timing issue between the woofers and ribbon. There is also no pre-ringing issue.
 

skid00

Member
Thread Starter
Joined
Mar 20, 2020
Messages
119
More  
Main Amp
2 x Adcom GFA 555
Front Speakers
Carver Amazing Platinum Mark IV
Thank you, jtalden!

I went back to other MDATs I recorded, and even the non-EQ'd showed that 'pre-ringing' effect.

I wish the audiophile media back in the day had reported honestly on these speakers. Only 'The Audio Critic' seemed to give them a chance, which is why I bought mine.

When these give out, I will either exclusively use headphones, or maybe go crazy and buy the latest Carver speakers. I'd have a really hard time spending that much money, though!

These speakers really show up bad recording techniques... :greengrin:
 

Jose Sifontes

Member
Joined
Jul 14, 2018
Messages
43
Location
Thousand Oaks, CA
More  
Preamp, Processor or Receiver
Denon AVR-2400H
Universal / Blu-ray / CD Player
Oppo 203
Front Speakers
SVS Prime Monitors
Center Channel Speaker
SVS Ultra
Subwoofers
Rhythmik FV15HP
Other Speakers or Equipment
Harbeth 30.1, VPI Aries TT
Video Display Device
Optoma UHD50
Screen
Elite Screens 100" (powered)
Remote Control
Several Harmony
Streaming Subscriptions
Rogue 99, Rogue ST-90, CI Audio D-200MkII
I also owned those barndoors (my endearing term for them) for several years and cannot tell you how many REW sweeps I did of them in search of perfection. The results you are getting there are very decent - you may want to say thank you to the shape and size of your room!

Are you running the original passive crossover? They get even better with an active line the miniDSP 2x4 HD.
 

skid00

Member
Thread Starter
Joined
Mar 20, 2020
Messages
119
More  
Main Amp
2 x Adcom GFA 555
Front Speakers
Carver Amazing Platinum Mark IV
I am indeed running the original, huge, crossovers.

Barndoors - I like it!

I wonder if peaked ceilings are better for dispersion? Do you have an opinion?
 

Jose Sifontes

Member
Joined
Jul 14, 2018
Messages
43
Location
Thousand Oaks, CA
More  
Preamp, Processor or Receiver
Denon AVR-2400H
Universal / Blu-ray / CD Player
Oppo 203
Front Speakers
SVS Prime Monitors
Center Channel Speaker
SVS Ultra
Subwoofers
Rhythmik FV15HP
Other Speakers or Equipment
Harbeth 30.1, VPI Aries TT
Video Display Device
Optoma UHD50
Screen
Elite Screens 100" (powered)
Remote Control
Several Harmony
Streaming Subscriptions
Rogue 99, Rogue ST-90, CI Audio D-200MkII
Vaulted ceilings *absolutely* help, IMO, from a standing wave (null) mgt as well as dispersion.
 

JLM1948

Member
Joined
Jan 12, 2019
Messages
124
"I *had* been running the amps strapped (800 watts), but had read that that destroys the damping factor."
Unless your amp has an appalling small DF to start with, bridging the amps won't change a thing.
Typically, the output impedance of a reasonable amp is under 0.1 ohm. With a typical 8 ohm speaker, the resulting effective DF - (DCR of speaker+amp Z)/Znom - is about 1.31. Bridging the amps changes the effective DF to 1.29. Nothing to write home about.
 

skid00

Member
Thread Starter
Joined
Mar 20, 2020
Messages
119
More  
Main Amp
2 x Adcom GFA 555
Front Speakers
Carver Amazing Platinum Mark IV
Top Bottom