again, based on 3 cu ft......
ScanSpeak Discovery 30W/4558T This looks good.
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@stevepa
If you can get the woofer cabinet dimensions so that we can get cubic ft or liters, I'll take a look around... If I understand the Monolith III correctly, it is 89db sensitivity and the woofer is passive (not powered)....
Being 4 ohm, you may find a good automotive woofer... the competition woofers are normally made for small boxes. I suspect we'll find something decent. Getting down to 28 hz in a small box will be the biggest issue. Get me box dimensions and we can all take a look around. |
@georgehifi
@stevepa
if it indeed 3 cu ft... this is expensive ($245 each), but ran curves F3 in QB3 alignment is 25hz
Peerless 835017
If the box is a smaller, there are others that can work for less money.
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Just thinking, if you are using electronic crossover and biamping, why do we care about matching sensitivity or impedance?
I still think that 83 is too low, you'd have to drive it pretty hard to keep up, but you could certainly use anything from 4 to 8 ohm from 87 to 92 sensitivity.
Based on that, I will expand the search. |
Hi guys, sorry on the Peerless recommendation, I don't know why I missed that it was 83db sensitivity.
@stevepa on the Peerless SLS 830669, it will go down to about 50 hz in a sealed box. I would not mind porting the box on the right driver, but this driver really wants a large box ported. Also, it has a very cheap frame. That does effect sound quality.
In 3 cu ft, the Scan Speak will work well. The Monoliths published crossover point is 125hz. I believe stevepa said that he was crossing electronically. Good excursion limits, however, with a qts of .32, you must vent or port your box with this woofer. If you do so, it will go be 3db down at just about 27 hz in an sb4 alignment or 24 hz in a qb3 alignment.
As it stands, I'd run this way without worry of distortion.
Of course box size could change it all.
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just ran curves on the SV12 in 3 cu ft sealed.... It'll be 3db down @ about 31 hz with a qtc of .79 |
Congrats on your subwoofer purchase @stevepa if you would, just go to the back of the box and get the woofer box measurements, we'll get very close on the cubic footage. I'd hate to see you buy the wrong woofer. Overall, I don't like over stuffing a box, (unless your box is too large) it actually raises QTC by limiting air flow, the woofer acts as though it is in a smaller cavity. A couple of other comments that were a bit off... Porting not keeping up with a sealed driver....Porting a driver in itself is not slower than a sealed driver... If optimally ported, speed should be fine... Of course similar to a sealed box, if you seal a driver to get a qtc of say 1.1, it will get boomy on you, if you seal it for a qtc of .6, it will get lean... on a ported box, you can easily affect the curve with the port. Overall though, I would also want a sealed driver if I could find it. I prefer the rolloff and they don't go out of spec as easy over time. Lastly a quote on driver cone mass slowing down the driver... Yes, if cone has less mass, it will be faster, but that would only be if 2 drivers had identical motor structure... with different motor structures, the cone mass alone cannot determine the speed of a driver. In fact, If you had a QTS of say .4 and you lowered the mass, qts would drop and sensitivity would rise, the driver would want a smaller box.... I have learned a ton from others on this site, so I don't want to come off rude or condemning, but I do want you to see the facts.
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again, stuffing in itself does not dictate speed.
A lightly stuffed box is what a woofer is normally spec'd at, as you add stuffing, a medium stuffed box, does give the woofer the illusion of a larger box by slowing down the flow of air inside the box, the air has to filter through the stuffing. When you over stuff the box, air flow cannot pass through and has the opposite effect. Air can't pass through at all and the woofer reacts as though it is in a smaller box.....Maybe we have a simple question in terms about the amount of stuffing (what is lightly stuffed or heavily stuffed) As I stated earlier, all things being equal, I prefer a sealed box sub myself. Sorry, but this is not opinion. It works this way.
In a sealed box woofer, I have many time added mass to raise qts so that a woofer would go down better in sealed box. The key there is "does the driver have enough motor & suspension to support the mass" I hope this helps, Tim |
@georgehifi Hi George, it sounds like you and I are just mixing terms of what is lightly, medium or overstuffed, but overall are on the same page.
@stevepa Steve, get the outer dimensions of your woofer box on the back of your monoliths. We can get very close to figuring its cu footage. We need that to stop guessing.
There were other woofers that did not go down as well, so if you are happy with that, using your New SVS sub, you'll be fine. I would only worry about resale later. I'd want a driver that went down well.
Get the dimensions and we'll go from there. |
@stevepa
Ok, assuming a 1 inch front baffle and 3/4 inch everywhere else, you're looking at 2.469 cubic ft... so if we model on 2 1/2 cubic ft, we'll get accurate results.
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@stevepa
If you are up for it, Jon Fo's idea for George is not bad either to raise the crossover point, The Good, removing the mid bass (100 - 300hz) off the panel, cleans up the mids and make for cleaner midrange.... The Bad is that you have a crossover point in the vocal region.
Its a trade off, but easy enough to do if interested.
Also, I have looked for this, but have not found it... the best single woofer that I know of for your application is an Tonegen 1259, also known as NHT 1259... Madisound had done a close copy called the Madisound 1259... so if you are looking around for the SV12, You could add this to your search... Good Luck, Tim
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Sorry George, Not sure where all of your info comes from, but adding mass in alone does not add distortion... In fact if the mass is a stiffener, depending on cone, it could decrease it.
@stevepa Steve, George and I could take you down 2 different roads. To be fair to George, I do not have his direct experience with your speakers, but in fairness to me, I come from a back ground of driver and speaker design. I speak from experience and an understanding of how all of this comes together.
The good news is that I do agree, that a good sealed woofer is the way to go. I have not found one that is really a great match for your Monoliths.... On the other hand, I have found 1 Dayton Pro, that would work very well indeed if you would be willing to port. It would be a very viable alternative. It seems George is questioning your measurements, if they are correct, you are at 2.5 cu ft.... Bean bags would decrease it.
I hope all of this helps, Tim |
"Sorry Tim but you clearly have no experience with mating esl’s"
But what I do have is a knowledge of how it works and why. I do understand blending panels and a woofer...
I know that you guys don't know me from anyone, but when Sumo designed the Aria speaker, they did call me for advice and way back when, The very company that you are speaking of Martin Logan did call me and ask me to come interview with them... which I declined.
I'm old and I've been involved in speaker design since I was 19. So rather that turning this worst and telling you what you don't know, I will bow out....
@stevepa can easily private message me if he needs help.
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Thanks for the kind words Steve. I'm glad that it worked out for you.
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