John72 Posted July 15, 2021 Share Posted July 15, 2021 Just purchased a Reference R-625FA and struggling to determine what size and brand of Receiver to buy. I have looked online, YouTube, etc. but wanted to know a recommendation from another Klipsch owner (especially) 625-FA. Not trying to go overboard - but still want to buy what I need. Any help would be great. Quote Link to comment Share on other sites More sharing options...
AndreG. Posted July 17, 2021 Share Posted July 17, 2021 Welcome to the Forum! Give us some more details please. Most important: On 7/15/2021 at 4:20 AM, John72 said: Not trying to go overboard What is Your limit? Very important, what is the rest of Your system (other speakers)? Roomsize (approximate)? And maybe You want to ask the Mod ( @dwilawyer) to move this thread to the dedicated HT section, that way more people, that can answer, will see Your post. I´m sure people will come back to You in no time. Quote Link to comment Share on other sites More sharing options...
garyrc Posted July 17, 2021 Share Posted July 17, 2021 Welcome to the Forum! Well, the speakers you have are rated at a sensitivity of 96dB at 2.83v (1 watt into 8 Ohms) at 1 meter, in a typical room. To translate that to likely AES measurements and to be conservative, call it 92 dB, but that's at only 1 meter away. Say you are going to sit 12 to 15 feet away, still in that typical room. How many watts per channel would you need, with all channels operating at once (which taxes the receiver or amplifier's power supply more than if you have just 2 channels operating) to provide THX's standard 105 dB instantaneous peaks from the main channels, not counting the sound below 80 Hz that will be bled off to a self powered subwoofer? Your self powered subwoofer will need to produce clean instantaneous peaks of 112 to 115 dB. For your home theater receiver, to power all of your main speakers/channels, my guess is at least a real 80 watts per channel, 8 Ohms, maybe 40 to 20,000, at low distortion (less than ~~ 0.08%??) with ALL channels you will be using operating, to properly strain the amplifier section's power supply. No doubt some people will point out the truth that Klipsch speakers are very efficient (sensitive), but given the problem of fudged home theater receiver specs (such as specifying power output at 1K only, or at a more favorable impedance, or at a high distortion level, or using some other deceptive practice, etc. etc.), I think it is better to build in a safety factor. Do you have just the front left and front right speakers (the R-625FAs) or do you have a complete array of surround, center, and Atmos speakers? Any additional speakers you get should be of more or less similar sensitivity. So, 80 watts per channel, with specs as seen above. OR, if you have a rather live room, with lots of early reflections, THX acknowledges that the peak level above 80 Hz can be lower than 105 db, because early reflections, and many of them, fool the brain into thinking the sound is louder than it would measure with an SPL meter, so maybe 102 dB peaks will do. If so, since each reduction of 3 dB in peak volume halves the amount of amplifier power used, a 40 watt per channel amplifier might, conceivably, do. Most decent home theater receivers start at higher power levels, though (last time I checked). You will want an AVR (audio visual receiver) or AVP (audio visual processor, which requires power amp(s) to go with it) with a subwoofer output (or two for expansion), so you can run 1 or more subwoofers. Naturally, your electronics, must have enough channels to support the number of channels you will have, and be set up for Dolby Atmos. You'll need to check the current features of each contender. Decent brands, providing you avoid the pitfalls discussed above (check magazine reviews that have "bench checks" to confirm specs, or come very close to what you need) are: Marantz Denon NAD Rotel and, if you have the money, McIntosh Luxman N.B. Since the sound levels we have been talking about are instantaneous peaks, they are O.K., unless we are talking about continuously loud sound, like some Rock, Metal, and electronic music. Here is OSHA's take: Since music (and movies!) can have a lot of bass, most people would measure with dBC, "fast," to pick up the bass. EDIT: for some reason the OSHA chart didn't come through, so I'll try again: 2 Quote Link to comment Share on other sites More sharing options...
Moderators Travis In Austin Posted July 18, 2021 Moderators Share Posted July 18, 2021 On 7/17/2021 at 12:30 AM, AndreG. said: Welcome to the Forum! Give us some more details please. Most important: What is Your limit? Very important, what is the rest of Your system (other speakers)? Roomsize (approximate)? And maybe You want to ask the Mod ( @dwilawyer) to move this thread to the dedicated HT section, that way more people, that can answer, will see Your post. I´m sure people will come back to You in no time. I would be happy to if OP would like it thete. 1 Quote Link to comment Share on other sites More sharing options...
AndreG. Posted July 18, 2021 Share Posted July 18, 2021 But it looks like we scared him away... And Gary put so much into his really good explanations. Quote Link to comment Share on other sites More sharing options...
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