So low bass needs extended treble for definition. I do have supertweeters, they work great enhancing ambience and stereo - i cross them over at either 20kHz or 15kHz, 1st order - and correcting for the 902A/811B droop which why i bought them. Will have to do some comparisons for bass quality, its not something i expected. What are my options for bass extension?
Options for bass extension. Dealing with the stuff below 100Hz is my biggest nightmare 
I suggest to get a cheap measurement microphone (like the often mentioned UMIK-1) and get an idea of your room response. Measure two different speakers placed in the same spot. If their response below 200Hz shows dips at the exact same frequency you first need to deal with room acoustics.
If not, congratulations, forward to the original question. Horn subs are possible. Search for "tapped horn".
I suggest to get a cheap measurement microphone (like the often mentioned UMIK-1) and get an idea of your room response. Measure two different speakers placed in the same spot. If their response below 200Hz shows dips at the exact same frequency you first need to deal with room acoustics.
If not, congratulations, forward to the original question. Horn subs are possible. Search for "tapped horn".
I have 4 of these: Cervin Vega b-36
Currently using just two, I need a second pair of strong hands to move in the other two Very happy with the bass, playing easily to 40 Hz.
Currently using just two, I need a second pair of strong hands to move in the other two
Very happy with the bass, playing easily to 40 Hz.Nice.What sort of cabinet for your 421s?
It is based on JC Morrison SLOB article and a down sized version of the v shape down firing one.
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I have 4 of these: Cervin Vega b-36
Currently using just two, I need a second pair of strong hands to move in the other two
What are you using to cover the first octave?
These are the best smoothest integration of all my attempts. I believe part of it is because the 421 8lf driver is very similar to the 416 so they blend well.
I use a minidsp 4th order slope with some boost centered around 25 Hz.
I drive them with Crown as amp.
I run my sub with a Crown amp with integrated dsp.
Mine wasn't ever a real slob as I always had it tucked in the corner so it could be seen as an infinite baffle with really huge reflex port. It worked nicely with the VOTTs (I have 515 Cs in mine). All the snap and is done by the VOTTs and the sub just charges up the room. It's totally different from a car sub. I'm struggling a bit to find the right terms but maybe a sensation that the air in the room is getting thicker and charged up with power makes sense?? It can be a very soft dense cloud but also tangible.
Lately I switched to a small rear chamber and reactance annulling.
Mine wasn't ever a real slob as I always had it tucked in the corner so it could be seen as an infinite baffle with really huge reflex port. It worked nicely with the VOTTs (I have 515 Cs in mine). All the snap and is done by the VOTTs and the sub just charges up the room. It's totally different from a car sub. I'm struggling a bit to find the right terms but maybe a sensation that the air in the room is getting thicker and charged up with power makes sense?? It can be a very soft dense cloud but also tangible.
Lately I switched to a small rear chamber and reactance annulling.
Actually nothing. I do not feel I am missing anything. I use a little EQ boost below 40 Hz and then a steep low cut. I think the corner placement plays a role as well. I like the sound of large horn based PAs, so that is what I have in my basement room
Hello ,
Pano is right again. Once i read that must be some kind of relation between the highest and the lowest frquency '' produced '' . I think they used an old line telephone to explain it. It is easy to make it go up in frequency but then it will be hard to listen to.
Probably the reason why the old tube based table radios sound well balanced, easy to listen too even though you had the idea it could sound a little more extended . But you could listen to it all day without getting tired.
I will be using a 12 db filter between pre- and power amps.
It would be nice if i can just blend in my two SVS active subwoofer with their built in SDS filter and using the Altecs 515 without any filter element to filter out let us say 40/60 hertz.
I dont know how Jean Hiraga blended the Magnat woofer with the Altec. Most people dont have the space to use VOT. I have but i cannot add anything more. I could add wings but it would be nicer to use the two active SVS subwoofers. They are kind of big but they blend in well with the other furniture.
Greetiings, Eduard
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Greets!
'Best' VOT - 'sub' woofer blend IME, especially with odd shaped acoustic spaces and/or with multiple open doorways attached cavities/nooks, is sealing off the horn driver to be strictly compression loaded and using the rest of the cab for a 'sub' woofer.
Second 'Best' IME, is experimentally determine the best overall XO point/slope within a ~Fs - 35 Hz cab tuning range.
'Best' in room blend usually requires multiple subs spread around the room to average out the worst room modes [after Dr. Geddes].
GM
'Best' VOT - 'sub' woofer blend IME, especially with odd shaped acoustic spaces and/or with multiple open doorways attached cavities/nooks, is sealing off the horn driver to be strictly compression loaded and using the rest of the cab for a 'sub' woofer.
Second 'Best' IME, is experimentally determine the best overall XO point/slope within a ~Fs - 35 Hz cab tuning range.
'Best' in room blend usually requires multiple subs spread around the room to average out the worst room modes [after Dr. Geddes].
GM
Depends on the horn's measured response for best results, but it's technically a half size 55 Hz horn = ~ a 110 Hz 1/4 WL horn, so to the first approximation make this the rear chamber's impedance peak and 'it is what it is'.
Measured, whatever flattens out the horn's response over the widest BW.
For example, the original's 803 horn woofer's successor, 416-8B, sims max flat at ~110 Hz [big surprise - not!] with 27 L net.
The much later 3154 [mid] bass BR woofer sims max flat at ~126 Hz [again, big surprise - not!] with 12 L net.
Ditto the 515B, 8G since these are optimized for the 'A' series ~70 Hz dual driver [mid] bass horn.
In short, block off the driver's area and keep adding solid 'waste' to 'taste'.
GM
Measured, whatever flattens out the horn's response over the widest BW.
For example, the original's 803 horn woofer's successor, 416-8B, sims max flat at ~110 Hz [big surprise - not!] with 27 L net.
The much later 3154 [mid] bass BR woofer sims max flat at ~126 Hz [again, big surprise - not!] with 12 L net.
Ditto the 515B, 8G since these are optimized for the 'A' series ~70 Hz dual driver [mid] bass horn.
In short, block off the driver's area and keep adding solid 'waste' to 'taste'.
GM
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