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Thread: Looking For More Punch From My 2245, 4345 Clone

  1. #61
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by robertg View Post
    I just want to upgrade a bit. Or maybe spend more money.

    I've only used the later versions without issue: The D75A and the later D45 with all-black face and after later ergonomic (not round) knobs (there is no D45A that I'm aware of).
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."óGreg Timbers

  2. #62
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    I ended up buying a Krell KSA-50S. It's a 50w Class A amplifier. It sounds slightly better, or at least I think it does, than the Ramsa that's worth 1/10 the price. I don't exactly have golden ears either.

    Some music sounds so good on these speakers and some is just mediocre. Female voices sound excellent, I find myself listening to some Joni Mitchell songs that I don't really care for, but it sounds so good.
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  3. #63
    Senior Member edgewound's Avatar
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    Quote Originally Posted by robertg View Post
    I ended up buying a Krell KSA-50S. It's a 50w Class A amplifier. It sounds slightly better, or at least I think it does, than the Ramsa that's worth 1/10 the price. I don't exactly have golden ears either.

    Some music sounds so good on these speakers and some is just mediocre. Female voices sound excellent, I find myself listening to some Joni Mitchell songs that I don't really care for, but it sounds so good.
    50 watts is pretty miniscule for 4345. 300-400 watts would be better.

    As for the recordings, these speakers will reveal good recording vs. not so good recordings. Actually, most any decent speaker system will do that.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  4. #64
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    Quote Originally Posted by edgewound View Post
    50 watts is pretty miniscule for 4345. 300-400 watts would be better.
    This amp is just for 300Hz and up, below that for the 2245s I use a 550w Crest 7001. 50 watts seems like more than enough power.

  5. #65
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by robertg View Post
    This amp is just for 300Hz and up, below that for the 2245s I use a 550w Crest 7001. 50 watts seems like more than enough power.
    50 wpc might be a little light, but should certainly do the job in an ideal world 100 would be best.


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  6. #66
    Senior Member Ian Mackenzie's Avatar
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    Turn up the Lpads up full and it will be fine for most listening situations.

    That is like 98 db@ 1 watt sensitivity.

    Technically with bi-amping at 300 hertz crossover point you get approximately 50%/50% split of the power between the woofer and the mid horn array. As result you get 6 db crest factor which works out to about 4 x the headroom of single power amp in full passive mode. So with the smaller amp rated at 50 watts thats like 200 watt amp in passive mode with 98 db@ 1 watt sensitivity out of each loudspeaker. You have stacks of headroom on the woofer.

    They don't teach you that at Yale.

    For most genres you'd be hard pressed to hit 20 watt peaks using the 50 watt amp with 98db@ 1 watt sensitivity.

    Generally it will sound bigger rather than louder because you get quite a lift in linearity with the 2245H from 30 hertz up. The intermodulation distortion of these systems is also really low.

  7. #67
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    When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

    I was assuming a 25w amp would be fine? I guess you can't have too much power.

  8. #68
    Senior Member Ian Mackenzie's Avatar
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    Quote Originally Posted by robertg View Post
    When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

    I was assuming a 25w amp would be fine? I guess you can't have too much power.
    Up to a point that is true.

    However, in domestic use the lust for power is sometimes about the notion more detail and clarity comes with loudness. Loudness certainly creates impact and a visceral soundscape.

    Unfortunately turning it up louder is not the answer if the resolution of the power amplifier is not there in the first place. The desire to EQ a system can also be about the desire for clarity and resolution. Looking for whatís missing?

    In my experience if you canít hear what you want to hear at mid and high frequencies with 1 watt then start looking at a more transparent signal path.

  9. #69
    Senior Member RMC's Avatar
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    Hi Robert,

    RE "I was assuming a 25w amp would be fine?"

    The following pic should give you some additional insight in figuring the power relations between the LF amp and HF amp in a biamped system, info is from Furman Sound electronic crossover Owner's manual I have. Other crossover manuals from gear i own (Rane and Ashly) don't mention this LF/HF amp power relations.

    Does the Krell, or Mc Intosh multi-channel amp for that matter, have a highly regulated power supply, or is it able to provide some dynamic headroom that the other can't deliver? Music dynamic range also comes into play. Don't forget the difference between the Crest and Krell amps is a 10:1 power ratio. If other things were equal, and they probably aren't, that would represent a 10 db level difference.

    On another matter, i noted you mentioned a while ago having some issues with Integrated Circuits, as i recall your tech mentioning counterfeit ones, poor China copies or some defective units? So by the same token i'm adding another pic from the same Furman Sound manual about what they have to say regarding IC reliability. Don't recall seeing this elsewhere in a manual either. Regards,

    Richard

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  10. #70
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    Quote Originally Posted by robertg View Post
    I'm trying to get more punch or kick out of a 2245. The system that I had before my 4345 clones had dual 15" 2226 drivers. It had some serious kick.

    My amp is a RAMSA WP9440 with 350 watts, I'm thinking I should try a bigger amp first? Maybe 6-700 watts?

    Would a 2240 or 2242 be a direct replacement for the 2245 without changing the tuning? I'm not sure if I really need much below 50Hz, I just listen to 70s music, no home theatre.
    Greetings -

    If more articulate, solid bass is what you're trying to achieve, I have had luck using larger than normal vent diameters. Up to six inches in some cases. Large vents will reduce the Mach number to zero. The down side, is that the larger the diameter, the longer the vent must be depending on the enclosure volume and tuning frequency. Vents are not required to be on the baffle. They can be placed anywhere on the enclosure as long as they are not obstructed. The frequency at which they allow the enclosure to resonate is omni-directional. Cutting a vent so as to be angled, or using PVC elbows may solve real estate problems that may occur. Keep in mind, a vent is considered a separate element in the acoustical circuit. In short, they take up physical volume, including the volume of the internal effective length. I am unsure if canned programs take that into consideration. You would be tuning a reduced volume enclosure to achieve the same frequency of resonance. I have found that tuning the enclosure to the resonance frequency of the driver increases articulation. I know some folks and manufacturers like to tune an enclosure a bit higher in frequency, some even a bit lower. Increasing amplifier power isn't always the solution to a simple problem.

    On a side note; Your wrote that you don't need much response below 50Hz because you listen to 70's music. The E string on an electric bass guitar is approximately 40 Hz. So yes, you would want the response to reach at least 40Hz. You would have no problem achieving that frequency and below with the 2245. Better to have the capability, than not.

    Good Luck,

    H.F.

  11. #71
    Senior Member 1audiohack's Avatar
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    I built a 10 cubic foot 4345 sorta inspired system with a 2245, 2123, 2451J on a 4338 horn. This system is three way active. After all the measuring and tuning was done I sent a sine wave through the middle of the passband of each driver and measured the voltage to see what the real world power requirements were to select the MF and HF amps for the rack. This is something I always do as the results are sometimes surprising.

    I planned on using a 350 watt per channel Crown K1 on the 2245. It turns out the voltage ratio is 3.2 to 1 to 1.

    How is that possible you may ask? The 2123 needs a bit of a push on the bottom of itís pass band to match the dynamics of the 2245 at 250-300 Hz. The 2451SL-4338 has an 18 dB SPL haystack hump in the middle that needs to be cut down to get to the Harman curve and even more if you want it flat.

    The K1 is a 55 volt supply.
    The 2123H wants a 28 volt supply. 100W into 8 Ohms
    The 2451J wants a 28 volt supply. 50 into 16 Ohms

    I listen to something with wide dynamic range while watching the voltage peaks on a scope.

    So, if you want to preserve the live dynamics of well recorded music, you need a lot more than flea power.

    For the record, I donít like any more gain than necessary. Itís space, noise, heat and expense. But, if it doesen't jump with the music, I find no satisfaction in it. It has to have enough.

    Your mileage may vary. It depends on what you prioritize.

    Barry.
    If we knew what the hell we were doing, we wouldn't call it research would we.

  12. #72
    Senior Member Ian Mackenzie's Avatar
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    Hi Barry,

    See section 1.3, 1.4 and 1.5 in this article.
    https://sound-au.com/bi-amp.htm

  13. #73
    Senior Member Ian Mackenzie's Avatar
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    Robert,

    How long have you had the Xilica XP4080 active crossover?

    What is your main source component?

  14. #74
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    Quote Originally Posted by Ian Mackenzie View Post
    Robert,

    How long have you had the Xilica XP4080 active crossover?

    What is your main source component?
    I probably bought it around Christmas or so.

    I have a Cambridge Audio DacMagic Plus DAC, Sonos Connect, Sony CDP-D12 CD player, Mcintosh C2200 tube preamp, Crest 7001 amp for the 2445s, and a Krell amp KSA-50S.

  15. #75
    Senior Member Ian Mackenzie's Avatar
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    Quote Originally Posted by robertg View Post
    When I crank it up the clip/limit light on the 550w Crest 2445 amp are my limiting factor. When I was quad amping I used a 25w multi channel McIntosh amp on the top three. I could never make the power guard lights come on.

    I was assuming a 25w amp would be fine? I guess you can't have too much power.

    It’s depends on a number of factors? Like the genre of music, your preferred listening distance to the 4345’s and the level you find comfortable.

    I personally have grown shall we say old of turning it up to a level neither l nor my neighbor can tolerate continuously. You have to ask yourself what is the point?

    Then your have industrial deafness. A lot of musicians and people in the PA industry have that problem. They won’t admit to it but they have it.

    Back to your plan l recommend you stay with the Krell as an
    Upgrade End Point. I recommend you try an alternative source as a point of comparison.
    If you are running an all digital signal stream your crossover may suffice. But l think saw a Mac Preamp?

    If that is correct and you have an analogue signal into the pre amp and analogue signal out then there is potential for improvement with a high quality analogue crossover network.

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