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I'm showing the worst case scenario to make a point. A shoebox type room, no treatment with the speakers at the shorter wall, close to the room corners. There are certainly ways to improve my situation.
A shoebox type room is not necessarily a bad room to start with; trying different speaker locations and some room treatment might bring much improvement.
The Concertgebouw in Amsterdam is a shoebox type concert hall; it has about the best acoustics of all concert halls world wide. Another one, the Vienna music hall, is also of the shoebox variety.
Not exactly cheap and it only deals with the bass region, but Velodyne's SMS-1 usually gets very good reviews. It can display the room's response and its problems and then (mostly) correct it with an 8-band parametric equalizer, continuous phase control and other features. IIRC it can be used with any brand of subwoofer.
Another very affordable tool is a mini dsp.
When you take the time you can experiment with all possible configurations (equalization; filtering in case of multi-amping). In the end your own ears will tell. Use appropiate source material like male voices. With organ music it is not so difficult to locate and treat standing waves; just a suggestion.
Originally Posted by boris81
Hopefully these graphs will illustrate what we are talking about.
The 1st graph is the frequency response of my speaker.
The 2nd graph is how that same response is affected by the room.
Attachment 255087
Even the best speakers are at mercy of the room. And my room sucks.
In fact, just "fixed" a serious LF hole in the response in a control room by simply blocking off an entrance to another room, made the LF response far more even throughout the room, and eliminated the LF suckout that was happening at the client couch.
The most affordable tool to start with is a dB meter, your ears, and filtered pink noise of various low frequency frequency bands. Pink noise will give results more similar to music than sine waves
Various sine wave and filtered pink noise are available for free as downloads, or on test CDs.
Free RTA software is available too.
Hopefully these graphs will illustrate what we are talking about.
The 1st graph is the frequency response of my speaker.
The 2nd graph is how that same response is affected by the room.
Attachment 255087
Even the best speakers are at mercy of the room. And my room sucks.
Boris' room is actually fairly good, better than many recording studio control rooms I have measured.
In fact, just "fixed" a serious LF hole in the response in a control room by simply blocking off an entrance to another room, made the LF response far more even throughout the room, and eliminated the LF suckout that was happening at the client couch.
The most affordable tool to start with is a dB meter, your ears, and filtered pink noise of various low frequency frequency bands. Pink noise will give results more similar to music than sine waves
Various sine wave and filtered pink noise are available for free as downloads, or on test CDs.
Free RTA software is available too.
Attachments
nice speakers, I once listened to a pair of Infinity's that looked almost identical except that the midranges were cones not ribbons. nice relaxed sound, very musical.
Those cone-mid speakers would be the RSII. The EMIM planar mids are extremely transparent now that I replaced the stock planar mylar diaphragms with true ribbon kaptan units made by Apogee Acoustics in Australia, and no more worries about blowing them out - in fact I removed all the fuses from the speakers.
You can see my homemade external passive crossovers behind the speakers, too.
those were real speakers, nowadays there's a tendency towards cute little boxes with high WAF factor.
This is not a worthwhile pursuit in this sense. The issues that befall different parts of the spectrum (etc.) are not necessarily related, and further, some sre speaker related, some are placement related and some are just room related. So I wouldn't put much stock in a 'generic' room curve.
If you could see what your speaker looked like anechoically and compare it with your specific room/placement/listening position then you'll start getting information that you can use. You'll just need a reasonably good mic and some software.
Then deal with the modes, the reflection based cancellations etc. etc. separately.
If that's all it says, you can't assume anything, not even that 35Hz is the right number. It could be -6dB, or -10dB is common too.
If the new speaker bass drivers are not in the same location and same height as the old ones, you cannot assume anything about the old speaker measurement applying to the new ones.
You need subs! The more the better.so what do you then when there is practically no window for placement due to a small room and common sense considerations? I'm at the place where WAF becomes PAF (personal acceptance factor).
+1If that's all it says, you can't assume anything, not even that 35Hz is the right number. It could be -6dB, or -10dB is common too.
If the new speaker bass drivers are not in the same location and same height as the old ones, you cannot assume anything about the old speaker measurement applying to the new ones.
You need subs! The more the better.
Subs are easier. The more the better is subjective. The +/- dB is always in real specifications.
Read up on bi-amp.
P
How big is your space?
I guess the question is addressed to me. it's a 3x4 m room.
but what's biamping got to do with it?
tomorrow I'll take one of the woofers out to measure T/S parameters and do a sim to find theoretical bass response.
In my pursuit to a subwoofed (!) solution, I have some hard times to determine my options. There's 3 scenarios: a full blown DIY project -but it's winter here and I don't have space for woodworking-, a subwoofer kit -These are not very diversified and I really don't know what the result would be- and of course a ready made product.
I'm tempted by the latter; I just can't wait, I'm more interred at listening mysic that building it.
People suggested many brands but no one mentionned about the Martin Logans? The Dynamo 700 seems pretty neat. Any thoughts about it?
Thanks,
Martin.
I'm tempted by the latter; I just can't wait, I'm more interred at listening mysic that building it.
People suggested many brands but no one mentionned about the Martin Logans? The Dynamo 700 seems pretty neat. Any thoughts about it?
Thanks,
Martin.
Then get yourself a reasonable woofer or three (size and cost are not the only concerns and you'd be surprised how far you can push those and still get reasonable results). Put it in any half reasonable sized closed box from another project and connect it/them to a stereo amp that you may have lying around. Now come up with a way to cut the highs, preferrably something you can adjust.
Then set about finding the right location/level/phase and crossover frequency for it.
That's interresting... Does the usage of a Linkwitz transform circuit eliminates the need for an active crossover (like in the typical plate-amps) or is it to compliment it?
I'm tempted in building my own simple sealed 2cu.ft. with their 12" driver and a matched Linkwitz circuit to extend its response I just wonder how that circuit will integrate with a plate-amp. And they're in Canada too...
Regards,
Martin.
The Linkwitz transform is an adjustment method to enable a designer/builder to obtain the desired low frequency performance.
It is a specialised high pass filter with adjustable F & Q. It has nothing to do with crossovers.
BTW,
the LF performance of a midrange driver could just as easily be adjusted.
Then you could incorporate a crossover using that adjusted F&Q to perform well with a simpler crossover.
It is a specialised high pass filter with adjustable F & Q. It has nothing to do with crossovers.
BTW,
the LF performance of a midrange driver could just as easily be adjusted.
Then you could incorporate a crossover using that adjusted F&Q to perform well with a simpler crossover.
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