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BudmanV24
10-10-2013, 02:08 PM
What is the concensous on the highest rms power the m770s can handle relatively reliably?
Lets assume 120hz high pass on the amp. I'm currently running 100wrms to my cabin speakers and am not satisfied. I'm used to 200-400wrms per speaker in cars. Im thinking either 150 or 200 to the in boat speakers. Im also about to drop a pair of factory cans on the tower with m770s and was considering putting an mhd750 on them. With properly set gains and not being a bone head, but still wanting to jam out at the same time what are you guys running with success? Do I need to build my own replacement crossovers to handle this kind of power?

craig3972
10-10-2013, 05:48 PM
I have been running 3 m770's inboats off one JL m6450 ( approx 150wrms each) for two seasons. I got this idea from David at Earmark. 6 inboats total on two m6450's. They work well and I havent encountered any issues.
An mhd 750 on only two m770's is a lot of power for each of those, but used responsibly they should be fine.
My one complaint about using the mhd750 on two tower speakers is that they are operating on the same channel. Earmark David and I have had discussions about this topic, I feel that some of the audio effects are lost when only using one channel, David disagrees. I use my stereo mostly for partying on the boat (close range listening) I like the sound separation of two channels on the tower vs mono.

BudmanV24
10-10-2013, 08:26 PM
Yeah, I agree. I'm not super excited about the idea of a mono amp. I've got a JL m4300 sitting on the shelf that I pulled from my boat that I could use. At 14.4v that would be 225wrms x2.

Aric'sX15
10-10-2013, 08:29 PM
An mhd 750 on only two m770's is a lot of power for each of those, but used responsibly they should be fine.


bud... do you responsibly use your things??? :D

MLA
10-10-2013, 09:26 PM
With pods side by side on a tower, stereo is lost IMO. In-boats, different story, stereo is a must.

David Analog
10-11-2013, 09:19 AM
Here's a link to an article about using mono on the tower.
http://earmarkcaraudio.com/articles/STEREO_OR_MONO_ON_THE_TOWER.htm

I would rate power handling for the M770s at 175 to 200 honest watts per speaker run in the highpass mode and if run flat. There is going to be a difference in real power between a strictly regulated and unregulated amplifier. If you have the factory pods containing the forward facing lamp, a percentage of these pods are not airtight, and if not, this would have to be corrected in order for the speaker to reach its max power handling without serious risk. Pay close attention to whether you are using the 'T' (air suspension) version or 'C' (IB) version in the correct application. A single JL Audio HD750/1 is perfect for four M770s. However, that is way too much power for a single pair. This amplifier is underrated and does not lose power with a drop in voltage supply.

JimN
10-11-2013, 09:45 AM
Yeah, I agree. I'm not super excited about the idea of a mono amp. I've got a JL m4300 sitting on the shelf that I pulled from my boat that I could use. At 14.4v that would be 225wrms x2.

Do you really sit there and listen to the stereo separation and 3D qualities of the music mix when you're skiing/boarding, talking when the music is playing, towing someone or cruising to/from the area where you'll be skiing/boarding? Really? That would make you unique. Stereo is far less important than proper balance between instruments, full-range frequency response, low noise & distortion and coverage. Mono amps work fine- just maintain proper impedance and set the input sensitivity correctly.

JimN
10-11-2013, 09:47 AM
What is the concensous on the highest rms power the m770s can handle relatively reliably?
Lets assume 120hz high pass on the amp. I'm currently running 100wrms to my cabin speakers and am not satisfied. I'm used to 200-400wrms per speaker in cars. Im thinking either 150 or 200 to the in boat speakers. Im also about to drop a pair of factory cans on the tower with m770s and was considering putting an mhd750 on them. With properly set gains and not being a bone head, but still wanting to jam out at the same time what are you guys running with success? Do I need to build my own replacement crossovers to handle this kind of power?

Look at the crossovers- if they have 25V capacitors, they'll never last long- that's roughly equivalent to 100W into a 4 Ohm load.

David Analog
10-11-2013, 10:14 AM
I'm pretty sure that JL Audio uses a nice mylar or poly cap in the tweeter series application....and that's the critical one. I have yet to see any one of the crossover components fail even with big power.
The biggest power handling limitation is usually the thermal capacity of the midbass and tweeter voice coils. They cannot make them handle more power without degrading the sound quality.

BudmanV24
10-11-2013, 11:57 AM
I just figured that as small as those crossovers were they would be overwhelmed and allow unwanted frequencies to the tweeters. Or am I completely off target on basic principles of how they function? In one of my previous auto installs I had people mistake my crossovers (Goertz, Solen, Mundorf) for amps. While I was running 400wrms per speaker in that install the crossovers themselves ate up a lot of the power.

Note taken on sealing the enclosures as they do have lights.

And I keep my h/u (cmd-4, which I despise) flat...0 bass, 0treb.

David Analog
10-11-2013, 12:41 PM
I just figured that as small as those crossovers were they would be overwhelmed and allow unwanted frequencies to the tweeters. Or am I completely off target on basic principles of how they function? In one of my previous auto installs I had people mistake my crossovers (Goertz, Solen, Mundorf) for amps. While I was running 400wrms per speaker in that install the crossovers themselves ate up a lot of the power.

Note taken on sealing the enclosures as they do have lights.

And I keep my h/u (cmd-4, which I despise) flat...0 bass, 0treb.

The 770 has a second order highpass on the tweeter consisting of a series capacitor and parallel inductor. These components are very precisely matched to both the tweeter frequency response and the tweeter impedance response and are completely interdependent. The 770 is a precision reproduction instrument, with proprietary parts and domestically built. If the right cap or coil is not available, they will have it custom built. I wouldn't tinker with it. They took no cost-saving short-cuts and you will not have a problem with the crossover. Typically, the size of the crossover components have more to do with the frequency application and less to do with power handling before saturation.

craig3972
10-11-2013, 01:51 PM
Do you really sit there and listen to the stereo separation and 3D qualities of the music mix when you're skiing/boarding, talking when the music is playing, towing someone or cruising to/from the area where you'll be skiing/boarding? Really? That would make you unique. Stereo is far less important than proper balance between instruments, full-range frequency response, low noise & distortion and coverage. Mono amps work fine- just maintain proper impedance and set the input sensitivity correctly.

Yes I really sit there and listen. Really. I dont even play the stereo while boarding, its too noisy with the wind and motor going. I discussed the stereo mono debate with david online and wanted to know for myself, so I hooked up the speakers in mono and in stereo and I like the stereo better while standing on the swim platform listening.

If you wanna drive around the lake with "look at me" music blasting from your tower speakers while boarding, then mono would be fine.

imyourmaster
10-11-2013, 02:07 PM
Here's a link to an article about using mono on the tower.
http://earmarkcaraudio.com/articles/STEREO_OR_MONO_ON_THE_TOWER.htm

I would rate power handling for the M770s at 175 to 200 honest watts per speaker run in the highpass mode and if run flat. There is going to be a difference in real power between a strictly regulated and unregulated amplifier. If you have the factory pods containing the forward facing lamp, a percentage of these pods are not airtight, and if not, this would have to be corrected in order for the speaker to reach its max power handling without serious risk. Pay close attention to whether you are using the 'T' (air suspension) version or 'C' (IB) version in the correct application. A single JL Audio HD750/1 is perfect for four M770s. However, that is way too much power for a single pair. This amplifier is underrated and does not lose power with a drop in voltage supply.

David, talking about regulated vs unregulated amps...The same tech at JL that advised me against a series/parallel configuration on a jl 750/1 (because he said it creates an unbalanced distribution of power between the speakers in series) also told me that an unregulated amp would be a better choice for driving 4 tower speakers. I swear I'm not making this up. I love my current JL setup and have nothing but praise for the product. Hi reasoning was that a regulated amp would draw a battery down quicker whereas an unregulated amp would simply put out less and less power as the battery draws down. What is your thoughts on this?

David Analog
10-11-2013, 03:59 PM
David, talking about regulated vs unregulated amps...The same tech at JL that advised me against a series/parallel configuration on a jl 750/1 (because he said it creates an unbalanced distribution of power between the speakers in series) also told me that an unregulated amp would be a better choice for driving 4 tower speakers. I swear I'm not making this up. I love my current JL setup and have nothing but praise for the product. Hi reasoning was that a regulated amp would draw a battery down quicker whereas an unregulated amp would simply put out less and less power as the battery draws down. What is your thoughts on this?

The efficiency of an unregulated and regulated amplifier of the same Class D topology are exactly the same. The regulated amplifier will deliver more power to the speakers with a lower supply voltage while the unregulated amplifier will deliver less and less power as the voltage continues to sag. Anything that delivers more output power with the same efficiency pulls more supply current. Period. Here's how silly this issue is......if you want to pull the identical current and generate the same power as the unregulated amplifier as the voltage falls off then TURN DOWN THE VOLUME JUST A PINCH.
I could understand his point when applied to a boat back in the day of the inefficent Class AB Slash amplifiers that were strictly regulated. But with the overriding Class D efficiency of 60% higher, the arguement has no real merit today.
The reason you want strictly regulated is beyond power alone. Yes, a strictly regulated amplifier is built with a power supply that is about 30% more robust. But the real benny is sound quality and headroom. When you sit at rest for a long duration and the voltage is at 12.0 versus 13.5 while running, many have experienced the sound going 'thin' and losing its 'punch'. Not so with a strictly regulated amplifier. Also, how is a fine amplifier supposed to maintain optimum performance with the solid state components operated off a supply that is deviating by +/- 10%. That's not exactly within tolerance.
If you are running the system at voltages below 11.8 V you are abusing your deep cycle batteries. Consumer deep cycle batteries don't like cycles below 50% capacity.
Don't take a fine distinction out of context. It's just one element in the big marine audio picture.

imyourmaster
10-11-2013, 06:50 PM
The efficiency of an unregulated and regulated amplifier of the same Class D topology are exactly the same. The regulated amplifier will deliver more power to the speakers with a lower supply voltage while the unregulated amplifier will deliver less and less power as the voltage continues to sag. Anything that delivers more output power with the same efficiency pulls more supply current. Period. Here's how silly this issue is......if you want to pull the identical current and generate the same power as the unregulated amplifier as the voltage falls off then TURN DOWN THE VOLUME JUST A PINCH.
I could understand his point when applied to a boat back in the day of the inefficent Class AB Slash amplifiers that were strictly regulated. But with the overriding Class D efficiency of 60% higher, the arguement has no real merit today.
The reason you want strictly regulated is beyond power alone. Yes, a strictly regulated amplifier is built with a power supply that is about 30% more robust. But the real benny is sound quality and headroom. When you sit at rest for a long duration and the voltage is at 12.0 versus 13.5 while running, many have experienced the sound going 'thin' and losing its 'punch'. Not so with a strictly regulated amplifier. Also, how is a fine amplifier supposed to maintain optimum performance with the solid state components operated off a supply that is deviating by +/- 10%. That's not exactly within tolerance.
If you are running the system at voltages below 11.8 V you are abusing your deep cycle batteries. Consumer deep cycle batteries don't like cycles below 50% capacity.
Don't take a fine distinction out of context. It's just one element in the big marine audio picture.

David, don't take this fine distinction out of context....but I love you man!!! Please tell me you did not sign a non-compete. I hope you're still on a retainer at Earmark and I think you deserve to get paid for every reply you've posted on every forum. Many members would still be fumbling for answers if it wasn't for your precise and expert knowledge. I posted a question on this forum a few days ago asking if anyone could recommend a reputable and expert marine audio installer in the South Florida area...NOT A SINGLE RESPONSE! Are you kidding me??? Fort Lauderdale is considered to be the boating capitol of the world! Everyone has a boat down here...I see a lucrative business opportunity. I think you should step out of retirement and be part of a phenominal business opportunity in South Florida....where it's summer all year long. PM me....I really think we should talk.

Aric'sX15
10-11-2013, 07:15 PM
hey bud, check this link out and scroll down to the bottom where they seal off the tower speakers.

David, what are your thoughts on using dynamat to seal the cans?
http://www.earmarkcaraudio.com/install_MasterCraft-X-55.asp

David Analog
10-11-2013, 08:00 PM
hey bud, check this link out and scroll down to the bottom where they seal off the tower speakers.

David, what are your thoughts on using dynamat to seal the cans?
http://www.earmarkcaraudio.com/install_MasterCraft-X-55.asp

Nope. Earmark uses .125" thick aluminum plate. Dynamat is damping material (and it really works) but it can't seal up something as small as a pod with that level of internal pressure. In a low pressure door panel application....absolutely it would work.

Aric'sX15
10-11-2013, 09:26 PM
does it make a noticeable difference with the cans sealed completely like that? in other words, is it worth the work?

JimN
10-11-2013, 09:38 PM
I'm pretty sure that JL Audio uses a nice mylar or poly cap in the tweeter series application....and that's the critical one. I have yet to see any one of the crossover components fail even with big power.
The biggest power handling limitation is usually the thermal capacity of the midbass and tweeter voice coils. They cannot make them handle more power without degrading the sound quality.

Someone here launched a JL crossover and the fact that the crossover is totally sealed makes it too difficult to determine what went bad. There was no output from the HP and the tweeter was still operational.

BudmanV24
10-11-2013, 10:59 PM
does it make a noticeable difference with the cans sealed completely like that? in other words, is it worth the work?

Yes. A sealed enclosure for your mid will give you higher power handling, tighter response, more output, and less distortion. That's some of the reasons why we pull mids out of doors in cars and put them in kick pods.

Aric'sX15
10-12-2013, 12:12 AM
so add that to your mile long list of winter projects... lol

David Analog
10-12-2013, 10:11 AM
does it make a noticeable difference with the cans sealed completely like that? in other words, is it worth the work?

Sure it is. Look at it this why. You have to compress and rarify the air molecules within the pod to the same degree as you do external to the speaker midbass cone. In other words, the internal displacement has to match the external displacement. But since the pod is so small, this creates far more internal pressure than the external open air. With that much pressure it only takes a very small leak. If those positive and negative pressures are allowed to escape the pod then those waveforms are opposite (inverted) of the speakers's external radiation which causes direct cancellations below frequencies (wavelengths) that are longer half this distance. This condition also serves to undermine any damping of the speaker (not only the air springyness of the trapped air in the pod but the natural resistance of open air. So, there goes the midbass, control, SQ, and your power handling.
In an IB coaming speaker you do not need a small pod since the speaker is intended for this type of expansive cavity. This type of speaker is self-damped to a greater degree and less dependent on the air spring of trapped air for control. But you still must have the front to rear acoustic isolation.