Re: Doc modding Marantz imperial 7
Posted: Fri Jan 03, 2020 10:16 am
Ways to increase the efficiency of these speakers
* add more 5.25" mid bass drivers. The greatest increase in dB comes from having them closely coupled. That means having a few of them mounted on the top baffle as close together as possible. If the mids have their own amplifier then with clever wiring i can make a 4 ohm load which demands more current from the amplifier but still within safe margins. The load will be easy as there is no xover. Adding more drivers increases the required box volume though so no free lunch here.
The mids have the lowest efficiency out of all the drivers so adding more of these would be the way to go. Help from the room at the very lowest frequencies means i will not have to add more 12" bass drivers. Can't afford the extra box volume required anyway unless i go the in floor infinite baffle route (not written that off by any means).
Although i have added multiple tweeters the series wiring limits their output as does the fact they are not closely coupled (on different baffles).
*start with more efficient drivers - not going to happen, i am too invested in these drivers and at £10 a pop what's not to like. I have loads of bisonkit so it's a no brainer.
So i am going to end up with forward or up firing isobaric 12" bass drivers wired in parallel (or non isobaric in floor infinite baffle), several 5.25" mid bass wired in a combination of series and parallel depending on how many of them, several tweeters wired in a combination of series and parallel depending on matching output with the 5 inchers.
* add more 5.25" mid bass drivers. The greatest increase in dB comes from having them closely coupled. That means having a few of them mounted on the top baffle as close together as possible. If the mids have their own amplifier then with clever wiring i can make a 4 ohm load which demands more current from the amplifier but still within safe margins. The load will be easy as there is no xover. Adding more drivers increases the required box volume though so no free lunch here.
The mids have the lowest efficiency out of all the drivers so adding more of these would be the way to go. Help from the room at the very lowest frequencies means i will not have to add more 12" bass drivers. Can't afford the extra box volume required anyway unless i go the in floor infinite baffle route (not written that off by any means).
Although i have added multiple tweeters the series wiring limits their output as does the fact they are not closely coupled (on different baffles).
*start with more efficient drivers - not going to happen, i am too invested in these drivers and at £10 a pop what's not to like. I have loads of bisonkit so it's a no brainer.
So i am going to end up with forward or up firing isobaric 12" bass drivers wired in parallel (or non isobaric in floor infinite baffle), several 5.25" mid bass wired in a combination of series and parallel depending on how many of them, several tweeters wired in a combination of series and parallel depending on matching output with the 5 inchers.