I think you misunderstand me, i'm not trying to encourage you to colour your sound, there are fantastic and neutral monitors that are not boring as hell and dry like the NS10 (which is IMO coloured in its own way), like those from ATC or dynaudio for example. even mission audio has a nice closed active monitor that sounds quite good. you do not have to sacrifice listenability to have something that works well in the studio. I have also done work mixing for multimedia and video projects so I know what is required of a nearfield
I think you are confusing 2 completely different things.
The volume of the midrange is affected by the sensitivity of the driver, the listening distance and how much BSC you have in the speaker. For example, a driver in a box with some kind of BSC could put out 85 dB (at 1 m, 1W). If you add 3 dB for every doubling of the power you end up with 100 dB at 1 m with 32W. That's a really high SPL.
The type and dimension of an enclosure affects only the bass (F3 and the rate of decreasing level, the latter being also influenced by the room).
Ralf
The problem is: do you want a balanced speaker or not?
A balanced speaker is one with a flat response (don't consider distortion for simplicity). It is possible to create a bump in the response at lower frequencies, but I doubt you want it. But it is really difficult to have a flat response from, say, 20 Hz to 20 kHz. With a 2-way with a 7" mid-woofer in a typical ported box you can have a flat response only from 50 Hz and up, before you will have a rising response from 0 dB up to the level of the 50 Hz one (F3 in the 40-50 Hz zone). The same woofer in a sealed enclosure will be flat only from 100-150 Hz, but before the rising will be smoother (F3 slightly less than 100 Hz). Room interaction will change the response thou, but that's room dependent.
If you want to go lower you need a less efficient driver, or a larger woofer. No free lunch here.
Download Unibox (a free excel based application) or WinISD for simulate the bass performance of your preferred woofer.
Ralf
A balanced speaker is one with a flat response (don't consider distortion for simplicity). It is possible to create a bump in the response at lower frequencies, but I doubt you want it. But it is really difficult to have a flat response from, say, 20 Hz to 20 kHz. With a 2-way with a 7" mid-woofer in a typical ported box you can have a flat response only from 50 Hz and up, before you will have a rising response from 0 dB up to the level of the 50 Hz one (F3 in the 40-50 Hz zone). The same woofer in a sealed enclosure will be flat only from 100-150 Hz, but before the rising will be smoother (F3 slightly less than 100 Hz). Room interaction will change the response thou, but that's room dependent.
If you want to go lower you need a less efficient driver, or a larger woofer. No free lunch here.
Download Unibox (a free excel based application) or WinISD for simulate the bass performance of your preferred woofer.
Ralf
This one? Thanks man, but I'm busking in the third world.I'll save it for when I'm rich and famous.
All I had to go on was your first post, where you said "...I can allocate about $400..."
A 7 inch Revelator is about $225, so about 12% over your $400 budget for a pair. Where did I go wrong? Have you changed your budget?
I have presented WinISD and LEAP curves in posts 5,8 and 17.
Sorry, I should have been clearer. The "about $400" includes about $230 for the Sure amplification (and power supply), and the "DSP in a Box" for loudspeaker management. The Morels, @$110 each, brings it to about $450... One of the other options presented here, such as the Tang Band W6-1721, should keep me closer to my budget.
Sorry for badgering, but this is the one question I really need some clarity on, in terms I can understand. Will 70 watts @ 4 ohms be enough to power any of the above mentioned drivers in a small sealed cabinet?
Sorry, I missed that. However the ScanSpeak curve you posted is IMHO plain wrong. In a 8 l closed cabinet it is as nice as the Vifa and Exodus Anarchy drivers, but not in the league of a driver designed for a closed box.
For that it seems you missed the contribution from jerome69. The Seas CA18RLY is designed for a closed box 15-25 l with a F3 in the 60-65 Hz range. I doubt you can find a better sealed design with a good 7" driver. It should also be in your price range.
English is not my mother tongue, but I think I already answered in a clear way. Anyway I will try another time.
First, the dimension and type of the enclosure will only dictate the amount and behaviour of bass. Nothing else. The SPL of the midrange depends from the sensitivity of the driver and the amount of BSC you built in the crossover.
If you need the lowest possible F3, go for a ported design, if you prefer a slower roll-off go for a sealed design.
You didn't made clear what is your need. How far are you listening? Do you need party level SPL, normal high o "apartment" volume? How big is the room? It is reflective or not? Will be the speakers placed near a wall? The first two questions will dictate the choice of the driver and/or the number of mid-bass drivers you have to use. The last two/three questions will modify the bass performance, because they will change the room gain (under 100Hz).
As an example, if you listen near field at a moderate lever you won't need more than a couple of watts (see my first post). On the other hand if you listen for example at 2m at high levels you need a sensitive driver: 85 dB for 1W at 1m translate to 79 dB at 2m for 1W, so with 32W you will have 94 dB at 2m. It is enough for you? If not move to a different driver. The CA18RLY is a 90 dB driver, I think it should be OK.
I have speakers with a Peerless mid-bass rated at 87 dB. I did a partial BSC, so my system has an effective 84 dB roughly sensitivity. I have a 40W amp and I listen at 2.5m. Frankly I don't have any problem with max SPL.
Ralf
giralfino,
thank you for hanging with me here... things are becoming clearer.
You are correct. I had entered the "Vas" parameter wrong. The correct curve is attached herewith.
Thanks Jerome and giralfino. Also modeled herewith, thank you.
Actually I have, to some extent:
from post #12: "I'm looking to get reasonably true response down to 60 Hz in the near field (<6 ft), in a small, SEALED design, playing into a relatively small room (<1500 cu.ft.)."
Additional info: I will be sitting bang in the middle, 4-6 feet away. As for loudness - the way I calibrate my monitors is as follows: I play pink noise at -20 dB Fs and increase my monitor level till I see 85 dB on my SPL meter. During recording and most mixing, its not loud... but if I play a "mastered" CD of any new pop music at this level, it gets loud enough so nobody can converse in the (small) room, but I have a sub and its part the reason)...
The reason I want to build this is that I work in different rooms at different distances from the wall. Which is why the continuously variable crossover and parametric eq of the MiniDSP can help... bass roll off depending on proximity to rear wall etc.
My own room, where the speakers will be used most of the time is a heavily damped tiny room (approx 12' x 10' x 8'), with its share of non linearity below 200 Hz. I work out of one of the most expensive parts of Chennai... real estate is more dear here than it is in most of the state of New York!
Thank you, that is encouraging... it seems I might be able to manage with this cheap amp, after all
Please find attached herewith, freq response and spl graphs of the 4 drivers on my list. Here is what I noticed:
* the ex-Anarchy has the poorest spl in my circumstance... so its probably out.
* the scan-speak has the max spl, but also starts to roll off sooner than the other contenders.
* The Tang Band and the Seas have almost identical response curves, but the TB is a couple of dB more sensitive, with my amp rating.
Right now, in my mind, the choice is between the Tang Band (a company I'l lightly suspicious about, because they make so much cheap stuff) and the Seas. Anyone care to help me make the decision?
thank you for hanging with me here... things are becoming clearer.
You are correct. I had entered the "Vas" parameter wrong. The correct curve is attached herewith.
Thanks Jerome and giralfino. Also modeled herewith, thank you.
Actually I have, to some extent:
from post #12: "I'm looking to get reasonably true response down to 60 Hz in the near field (<6 ft), in a small, SEALED design, playing into a relatively small room (<1500 cu.ft.)."
Additional info: I will be sitting bang in the middle, 4-6 feet away. As for loudness - the way I calibrate my monitors is as follows: I play pink noise at -20 dB Fs and increase my monitor level till I see 85 dB on my SPL meter. During recording and most mixing, its not loud... but if I play a "mastered" CD of any new pop music at this level, it gets loud enough so nobody can converse in the (small) room, but I have a sub and its part the reason)...
The reason I want to build this is that I work in different rooms at different distances from the wall. Which is why the continuously variable crossover and parametric eq of the MiniDSP can help... bass roll off depending on proximity to rear wall etc.
My own room, where the speakers will be used most of the time is a heavily damped tiny room (approx 12' x 10' x 8'), with its share of non linearity below 200 Hz. I work out of one of the most expensive parts of Chennai... real estate is more dear here than it is in most of the state of New York!
Thank you, that is encouraging... it seems I might be able to manage with this cheap amp, after all
Please find attached herewith, freq response and spl graphs of the 4 drivers on my list. Here is what I noticed:
* the ex-Anarchy has the poorest spl in my circumstance... so its probably out.
* the scan-speak has the max spl, but also starts to roll off sooner than the other contenders.
* The Tang Band and the Seas have almost identical response curves, but the TB is a couple of dB more sensitive, with my amp rating.
Right now, in my mind, the choice is between the Tang Band (a company I'l lightly suspicious about, because they make so much cheap stuff) and the Seas. Anyone care to help me make the decision?
Attachments
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Have you looked at Zaph's site yet?
Zaph|Audio
Both the Seas and the TB are tested, with comments. Also use the comparison application to look at the frequency response and harmonic distortion. Look at the comments for the CA18RNX as well, since it is very similar and contains info about the response.
The Seas seems to have a slightly cleaner low end, but the TB has a better midrange, and is still fairly close to the Seas in the bass region. Since you're using it sealed, response below 50Hz is probably not going to be very noticeable. Personally I would choose the TB over the Seas in this case.
There's also the Dayton rs180 with its "very clean low end"; it is about 2dB less efficient, but you probably won't notice that much. The benefit is that it is half the cost of the others.
Zaph|Audio
Both the Seas and the TB are tested, with comments. Also use the comparison application to look at the frequency response and harmonic distortion. Look at the comments for the CA18RNX as well, since it is very similar and contains info about the response.
The Seas seems to have a slightly cleaner low end, but the TB has a better midrange, and is still fairly close to the Seas in the bass region. Since you're using it sealed, response below 50Hz is probably not going to be very noticeable. Personally I would choose the TB over the Seas in this case.
There's also the Dayton rs180 with its "very clean low end"; it is about 2dB less efficient, but you probably won't notice that much. The benefit is that it is half the cost of the others.
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Many times, but I only saw the comments, until now. Thanks for the pointer.
I'm a n00b, and can't claim to understand completely, but FWIW, i concur. The additional additional spl capability of the Tang Band is possibly a tipping point advantage.
Any more inputs welcome:
The Seas:
The Tang Band:
Attachments
Not very easy to choose :
-The TB seems to be a better driver with better distortion number in the high midrange and the treble but 4ohms
-The SEAS is a good driver but 8ohms
The sound of the loudspeaker depends of the ability of the amplifier to drive the loudspeaker !
If the amplifier is less stressed in the bass area, the midrange will be better.
Four ohms driver needs a more punchy amplifier in the bass in order to keep a good midrange.
-The TB seems to be a better driver with better distortion number in the high midrange and the treble but 4ohms
-The SEAS is a good driver but 8ohms
The sound of the loudspeaker depends of the ability of the amplifier to drive the loudspeaker !
If the amplifier is less stressed in the bass area, the midrange will be better.
Four ohms driver needs a more punchy amplifier in the bass in order to keep a good midrange.
thanks jerome69, but wow! don't know what to make of this. Are there amps that are specifically "more punchy in the bass"?
another thing that worries me is that I'm not sure (no pun intended!) if the sure power supply can actually pull out the said 70w@4ohms/30w@8 ohms from the (so called) 4x100w amp. Can anyone confirm this?
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