You talked about frying the amp and the speaker. This won't happen, unless you go daft with the sub 20Hz stuff. Before anything fries, you'll hear a farty noise during bass reproduction. This is the subwoofer running out of excursion. When this happens, you won't have long to turn it down (few mins perhaps) before things begin to break.
Seeing as you won't ask too much from it, go to 20Hz with the eq, let the room gain take over from there. It would be advisable to put the circuit in a seperate box, and have it switchable between circuit on/off. Leave it off when you're having a party. Rest of the time, switch on unless you want it loud.
Chris
Seeing as you won't ask too much from it, go to 20Hz with the eq, let the room gain take over from there. It would be advisable to put the circuit in a seperate box, and have it switchable between circuit on/off. Leave it off when you're having a party. Rest of the time, switch on unless you want it loud.
Chris
Well...That's a handy spreadsheet
I have toyed around with it a little this morning, and the results do look impressive! Especially for a smaller sealed box (70L). I am going to look at it some more this afternoon. This might make for an inexpensive solution to having an oversized box, but will still give me the lows that I am looking for!
With your experience with LT circuit, is there a noticable difference when it is on vs. off? Do the LT functions resemble what actually comes through when used in real life, even in a small box?
Thanks again for all your help!!
Walt
To reduce the box size to work effectively with an LT, you raise the Fb (box tuning) and if it is played without the LT circuit, it will have very low bass output.
Properly designing a sub to work with an LT starts with the driver - it needs to be suitable. You then work with a program like Unibox to find the optimal box size for this application, in this case it should be small enough to push Fb up. This pushes the drivers impedance peak up as well and gives the amp a better load to work into.
Once you have the Fb and the Qtc of the enclosure you can then work with the LT spreadsheet to find the component values for the circuit.
This was a summary, Rod Elliott explains it fully in his LT article on his site. Good reading.
Properly designing a sub to work with an LT starts with the driver - it needs to be suitable. You then work with a program like Unibox to find the optimal box size for this application, in this case it should be small enough to push Fb up. This pushes the drivers impedance peak up as well and gives the amp a better load to work into.
Once you have the Fb and the Qtc of the enclosure you can then work with the LT spreadsheet to find the component values for the circuit.
This was a summary, Rod Elliott explains it fully in his LT article on his site. Good reading.
For my sub (I think I posted response charts), there is a noticable difference - with the circuit, it sounds almost bottomless (impressive for a pair of 8"s), without the circuit, there's a lot more SPL available, but it doesn't go as low. With mine, I probably over did the circuit, and I should probably have had a target of 35Hz, but I'm pretty happy with it - my sats keep up, and the amp doesn't come out too badly either.
With the sub you're making, a smaller than optimum box will certainly sound deeper, without losing the lovely transient response that sealed boxes have.
So, yes, the graphs that it shows do come out in real life.
Important note - your hearing sensitivity isn't too good at low frequencies, so make sure your ears are attuned to the sub before you go making judgements.
For example, prior to my sub, I had a cheap 2.1 computer system. It went pretty low and pretty loud, but the way the bass sounded in comparison was terrible.
These circuits can be a lot of fun, especially for cooking low power speakers (we've all done it). For example, another pair of PC speakers, amp broke. Took the 3" woofers out, put one in a box and plugged the other into the nasty end of 50W and my LT circuit. Don't worry about your subwoofer though - it has a good amount of power handling, Xmax etc, so it will be fine until you really go for SPLs.
Chris
With the sub you're making, a smaller than optimum box will certainly sound deeper, without losing the lovely transient response that sealed boxes have.
So, yes, the graphs that it shows do come out in real life.
Important note - your hearing sensitivity isn't too good at low frequencies, so make sure your ears are attuned to the sub before you go making judgements.
For example, prior to my sub, I had a cheap 2.1 computer system. It went pretty low and pretty loud, but the way the bass sounded in comparison was terrible.
These circuits can be a lot of fun, especially for cooking low power speakers (we've all done it). For example, another pair of PC speakers, amp broke. Took the 3" woofers out, put one in a box and plugged the other into the nasty end of 50W and my LT circuit. Don't worry about your subwoofer though - it has a good amount of power handling, Xmax etc, so it will be fine until you really go for SPLs.
Chris
I've considered buying one of these for quite a while-
WM8 "BASSIS" Bass Correction Equalizer
I could do my own, but why reinvent the wheel and the PCBs are already done.
CH
WM8 "BASSIS" Bass Correction Equalizer
I could do my own, but why reinvent the wheel and the PCBs are already done.
CH
this is exactly where the LT comes into it's own.
You choose the low end reponse by setting the Q and the Frequency you want and the electronics sends the correct signal to the boxed speaker to achieve that target.
If you don't like it, then all you do is select a few resistors and capacitors to alter the electronics in the LT for your new target. The boxed speaker nevers needs to change.
You can experiment to your heart's content. It costs just a very few passive components. If you're real clever the variable (fixed) components can be inserted into dil sockets to make experimentation even easier.
Overkill? You must be new. A 15" in a Malibu Barbie dream house wouldn't be considered overkill on this site. Little things like drawing more than the 200amp residential service allows or causing seismic alarms that bring the Feds to your house might be the start.
I have a pair of 15" Selenium woofers in my living room and as mentioned, they can always be turned down if need be. They are very efficient and sound great but don't go real deep. They are for music and no HT so it isn't an issue.
You would probably be better off picking a whole design and building it instead of driver shopping and then calculating the enclosure. Browse the many different projects here and build the same spec enclosure using the same driver they used as the results are known. You can always start from scratch on a later project once you have more experience and the desire to experiment.
A 15" in a Malibu Barbie dream house wouldn't be considered overkill on this site. Little things like drawing more than the 200amp residential service allows or causing seismic alarms that bring the Feds to your house might be the start.I have a pair of 15" Selenium woofers in my living room and as mentioned, they can always be turned down if need be. They are very efficient and sound great but don't go real deep. They are for music and no HT so it isn't an issue.
You would probably be better off picking a whole design and building it instead of driver shopping and then calculating the enclosure. Browse the many different projects here and build the same spec enclosure using the same driver they used as the results are known. You can always start from scratch on a later project once you have more experience and the desire to experiment.
Walt,
I have two of the PCB for ESP project 71 if you are interested.
ESP - P71 Purchase Information
I have two of the PCB for ESP project 71 if you are interested.
ESP - P71 Purchase Information
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