Replacing 3-way speaker woofers with subwoofer driver
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Bronze Member Username: JodavisToronto, Ontario Canada Post Number: 36 Registered: Apr-09 | Both of my 3-way cerwin vega D-9 original 15" woofers got ripped around the foam with age and humidity. So I decided to look into replacing the woofers with 15" subwoofers instead that have more power, better solid basket and magnet strength. If I do this, will my entire speaker enclosure get ripped apart by upping the wattage from 250rms to 500rms? Will I likely have to upgrade the internal crossover? Will the sound be greatly affected from the change of drivers? The woofer both speakers are using are exactly these kinds: The subs I want to put in are these: https://www.amazon.com/Dayton-Audio-RSS390HF-4-Reference-Subwoofer/dp/B00JZTHLJU |
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Gold Member Username: SuperjazzyjamesPost Number: 1776 Registered: Oct-10 | My suggestion: Get in touch with Cerwin Vega or a parts dealer and get as close as possible to the original woofers. You can't just throw any driver into any cabinet and expect it to sound good. You'd have to find subwoofers with the same Thiel-Small parameters as the stock woofers for one thing. For another, subwoofers are greedy and suck up all the power. This is why most subs on the market are powered (have a built in amplifier). Passive (nonamplified) subs are usually powered by a dedicated external amp. In addition, depending on the sub's frequency range, you might have a gap in the mid-bass region. As for watts ripping your cabinet apart, not gonna happen. Cabinets don't care in the slightest how many watts the drivers are getting. Subwoofers do not have more power than woofers. Assuming you buy a sub or subs from a company that differentiates between woofers and subwoofers, The sub will have deeper bass response and possibly sound punchier than a woofer. Btw, ignore the power handling spec. It has no meaning whatsoever. |
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Gold Member Username: MagfanUSA Post Number: 2656 Registered: Oct-07 | Even less expensive would be to refoam the woofers. Kits are inexpensive an with some patients, can be done by regular folks. changing woofers will result in worse performance since the cabinet was designed FOR the woofers it has. You would need to know the TS parameters of the original woofers to find a match from what is now available. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 17037 Registered: May-04 | . "For another, subwoofers are greedy and suck up all the power. This is why most subs on the market are powered (have a built in amplifier)." That's not at all true, james. "You'd have to find subwoofers with the same Thiel-Small parameters as the stock woofers ... " Not "the same". Woofers operate in an enclosure which has been designed around the TS parameters of the driver. While it's true you cannot stick any woofer - there is no real difference between a "woofer" and "subwoofer" - in any cabinet and expect good results, there is considerable felxibility in the driver you can use as a replacement. However, the type of enclosure used for the original CV's will limit your selections to those drivers meant for a vented cabinet of generic dimensions. In other words, a driver meant for a 1 cubic foot enclosure will not work well in a 3 cubic foot enclosure and vice versa. Contact Parts Express and they will likely have a Dayton driver which can be sub'd for the originals; Changing the crossover is unlikely - particularly with the CV's which have wide tolerances for their parts. But it would be best for you to know at what frequency CV spec'd their crossover before you contact PE. If nothing else, provide PE with the link to the reconed wooofers on eBay. The sound is likely to change somewhat with different drivers in the box. How much you might notice is up to you to determine. "Cabinets don't care in the slightest how many watts the drivers are getting. " For the most part, this is true. . |
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Gold Member Username: SuperjazzyjamesPost Number: 1777 Registered: Oct-10 | "For another, subwoofers are greedy and suck up all the power. This is why most subs on the market are powered (have a built in amplifier)." "That's not at all true, james." "there is no real difference between a "woofer" and 'subwoofer'" Actually Jan, while it's true that some companies don't differentiate between woofers and subs, some do and those that do, do so for a reason. I may have told you this before, but I once installed a HT system in a bar. I had advised the owner of the bar to buy a powered sub instead of a passive one for the very reason I mentioned about subs sucking up all the watts. He didn't listen and bought the passive model. Every time there was a heavy bass passage of any sort whether in a movie or music, the bass was all that could be heard because the subwoofer was sucking up all of the watts. So if a drummer hit the bass drum and a cymbal at the same time while other instruments were playing, the sound of the bass drum was the only sound heard. Now, if you can tell another reason for this, I'm all ears. Otherwise, I don't see how sound can be effected this way if not for the sub being greedy. Why else would subs be powered? |
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Gold Member Username: MagfanUSA Post Number: 2657 Registered: Oct-07 | Actually, the 50:50 power point for normal musical material is about 350hz. Keep that in mind if you ever go the biamp route. Power needs below say...about 50hz go down fairly quickly, again with music. HT / Movie is another matter, but than a sub with solid musical credentials is not necessary for car crashes or bomb explosions.. The reason the bass was so overpowering in the bar setup? Well, 2 reasons occur right off the bat. First, poor location of sub. Second would be poor setup with the gain too high. Other reasons like too high a crossover and a few others are on the list, as well. Running the sub against full range speakers can produde midbass bloom which just sounds slow. My HSU easily keeps up with my panels. HSU is 250 and the panels have access to about a kilowatt. Level control on the HSU is at about 10:00, no higher. And the low sensitivity of panels is well known. Power greedy sub? hardly. Though it is vented and presumabely of much higher sensitivity than the panels. Subs for HT are also working against the normal HT amp, which is anemic at best. Even the 100x7 variety would be lucky to kick down 60 or 70 with all channels driven. And than only into an 8 ohm resistor. Certainly not into a reactive load of 4 ohms. Also, the usual person doesn't get full range main / center speakers. The standard crossover is set at 80hz for that reason. As for the bar setup with the passive sub? I'm sure it was simply a poor match for the mains. Physical setup problems also apply. And unless the sound sytem drove people OUT, I'd expect a room full of people to help dampen a slight overdone bass. Anyway, the OP has a few options. Get a CLOSE match woofer from Parts Express. That'll certainly work. He could also do a refoam, which I note Jan didn't object to. |
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Gold Member Username: SuperjazzyjamesPost Number: 1782 Registered: Oct-10 | Leo, I appreciate your input, but the bass overpowering was not the problem. What happened was, the signal above what ever the fixed crossover point was would dip in response to bass. So if Mariah Carey was playing, every time the bass drum was hit, her voice and all other musical instruments were actually dipping in volume for about a second after the bass drum signal passed. Turning on the loudness switch helped reduce this problem and while using tone controls for boosting any part of a signal goes against my grain, turning the bass all the way up further reduced the problem, but did not eliminate it entirely. Btw, we did try moving the sub around to no avail. |
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Bronze Member Username: JodavisToronto, Ontario Canada Post Number: 37 Registered: Apr-09 | I actually figured something out where I won't have to worry about changing the internal crossover. If i put a subwoofer in, I won't connect it to the crossover in the 3-way speakers period. What will end up happening if i do is the subs superior power intake from the original woofers will cause the mids and highs to blow way before the sub will. My idea is to leave the crossover for just the mids and highs and run the subwoofer driver with it's own wiring directly to the subwoofer power amp via LFE port or FRONT RCA mains which means ill have to drill a few holes in my speaker cabinets and seal it off. However finding out my T/S parameters to determine how well the driver will perform is still a b*tch I have to find out. |
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Gold Member Username: SuperjazzyjamesPost Number: 1785 Registered: Oct-10 | First off Julien, if you intend to do what I think, which is to run a line from your subwoofer/LFE output on your preamp to your subs. This won't workout. You'll need a power amp between your sub out and your subwoofers. Otherwise, why do you need to drill holes and seal off anything? No offense, but your entire post #37 makes no sense at all. I still think refoaming your woofers of replacing them with similar woofers would be all around a much better idea than anything you've suggested thus far. |
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Bronze Member Username: JodavisToronto, Ontario Canada Post Number: 38 Registered: Apr-09 | I know I need a power amp between my preamp, obviously, the sub I'm intending to get is 800 wrms. lol, the least I could do if I wanted to be an A**hole to the sub is give it 800wrms to match up, but my intentions are to power it slightly over at a good 1000wrms clean. However I'm not worried about my amps and hookup in those terms, I'm just worried about my 3-way speaker cabinets blowing to bits upgrading from the stock 15" 150/200watt rms woofers to 800 watt rms subwoofers. My intentions of what I want to do "superjazzyJs(me)s" are explained as simple as possible. 1) Poorly made woofers get tossed. *thud clunk*! 2) better 15" subs get put in and decided to avoid connecting them to the existing 3-way crossover as: the subs power will way override the mids and highs, the wiring will be much thicker, shoving basic speaker wire in push terminals if an 800 watt sub were to be attached to the crossover logically doesn't sound plus dangerous so.. 3) the subs get suitable wiring and get ran through the box (or I buy a suitable terminal for them). Therefore, my existing crossover is only being used for the mid and highs so don't have to worry about damaging it from too much power or re-tuning the crossover. 4) Plenty of power will be fed I got that laid down pat. My worries? 1) even though my 3-way cerwin vega boxes are as big as from my waist down and have to circular ports in each box, will it blow it to bits from too much pressure? 2) How much will the sound realistically change just from using a different driver? I will upload pics of my pair of cerwin vegas tomorrow of how big the enclosure is and where everything is placed. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 17058 Registered: May-04 | . "My worries? 1) even though my 3-way cerwin vega boxes are as big as from my waist down and have to circular ports in each box, will it blow it to bits from too much pressure?" How much "pressure" do you intend to exert? You will have control of how much volume and, therefore, how much pressure the system will experience. The most basic rule of home audio is, "When you hear distortion, turn it down." You sound like you are more experienced in car audio which has completely different rules. 800 to 1k watts into a Cerwin Vega is a little absurd as the CV's are electrically quite high in sensitivity; normally around 96dB @ 1 watt. In the average room that would mean you would reach levels which will cause hearing damage with about 100 watts. While having more watts than will ever be required is beneficial, you've sort of reached the overkill and then kick it down the stairs level at 1k watt. The idea you have is, I would say, only partially thought through. You haven't said you've made any attempt to match the "subwoofer" with the old CV woofer. Have you? If not, there are several problems you will encounter with your plan. Whether you notice them I can't tell since you will probably be listening for signs your cabinets are being torn apart. As leo and I mentioned in our earlier posts, low frequency drivers operate in cabinets designed for their TS parameters. These parameters dictate first of all the total enclosure volume; how large the enclosure must be to achieve the stated low frequency response, transient response and output levels. Once the enclosure volume has been settled on, the TS parameters also instruct the builder how to go about venting the box and the total volume of the vent; length and diameter plus any specific instructions regarding how the port might be shaped. If you ignore these basic parameters, you will not achieve the promised results from the driver you select. In other words, you just can't stick any driver in a pre-existing box and expect great results. So, the first question would be, have you done the homework required to make an acceptable match between the driver and the boxes/vents you intend to use? Have you matched all of the specs for the new driver to the old? Or, have you just decided to use a generic "subwoofer" in place of the old driver despite the inconsistencies between the drivers? If you have made certain the drivers are compatible with the enclosure, crossover and other drivers you have, then you need to go back to the drawing board and start over. Next, the existing crossover in the CV's is very likely to have included a low pass filter for the woofers. A low pass filter in this case would have rolled out the woofer's response above a set frequency. If you ignore the filter, you must now come up with a way to limit the new woofer's output above that same frequency. A typical filter on a plate amp provided with most subwoofers will not have a crossover point high enough to match the CV's crossover nor will it probably have the same filter order - what determines just how rapidly the woofer's output is curtailed. If you do not bother to match the old to the new, you will likely have one of two problems arise. First, the new woofer, being a "subwoofer" type will not reach high enough to make a smooth transition to the midrange driver's output. This will result in a hole in the frequency response of the speaker system. Alternately, if you do not cut off the driver's output at a frequency similar to the original, the driver will continue to output signals well beyond the point CV had set as the best cutoff for the cross to their midrange driver. Now you will have too much output from two dissimilar drivers operating in the range where your ears are most sensitive to such problems. Given the typically large vents in most CV's, you will also have far too much output in the midrange which will be existing the port. This will only add to the issues of inaccurate frequency response as this information is coming from the backwave of the drivers and will, therefore, be out of phase with the direct information from the front of the drivers. This will result in poor group delay of the system and irregular frequency response. Basically, you could really "F" this speaker up. What all that adds up to is your second question; "2) How much will the sound realistically change just from using a different driver?" Without any further information regarding any attempts you've made to match drivers and crossover points, I would say you will probably have a reasonably bad sounding speaker. You will certainly have a very different sounding speaker than the original CV. Driver materials will make up a large portion of what you can expect to be "different". CV's with a paper cone woofer will sound different than CV's with a poly cone woofer or a doped paper woofer. If you've not matched the TS parameters and accounted for the differences in driver output at upper frequencies, then you've created a totally new speaker system. A new speaker system can't be expected to sound like an old speaker system. Then, if you've not matched the sensitivity of the old woofer to the new, you might not be able to make a smooth transition from the high efficiency mid and upper CV drivers to a completely different low frequency driver. Bottom line, you can't just stick new woofers in old speakers and expect a good result. That's why I suggested you contact Parts Express to get some informed advice on how to go about this project. As is, I'd say your chances of a good result with the plans you've laid out are minimal. If you call PE first and take their advice, your chances have improved expotentially. Contact Parts Express. . |
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Bronze Member Username: JodavisToronto, Ontario Canada Post Number: 39 Registered: Apr-09 | Alright, seeing as I have work today and a full 3 day weekend to myself, I guess I'll be getting around to whipping out some calculations "Jan Vigne". The sub that I want to get was through parts express so calling them would be a good start (probably e-mailing is better). When I gather up all the details about my speakers and subs, Ill post you back. For now, here are some pics of my speakers im referring to:      As you can see in the pics, the box (cabinet) is pretty big and more modern looking than the brown old looking D-9's. One speaker has the woofer taken out and the other has the good one still in. The shot with the two circles(cylinders) are the ports. Sorry if I technically called them 3-ways as there are four drivers. These speakers mids and highs were upgraded from the original cerwin D-9's bad sounding mids and highs. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 17059 Registered: May-04 | . The "ways" come in when you count the number of divisions of frequency, not the number of drivers. Probably, the two, what?, four inch drivers are both midrangers covering the same frequency bandwidth. If that's the case, they would be arranged in M-T-M style and they would still be three way speakers, "Julien". |
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Gold Member Username: SuperjazzyjamesPost Number: 1789 Registered: Oct-10 | Again, your cabinets won't be harmed. The only thing that's obvious to me is that you intend to do what you planned regardless of what anyone tells you. So, go ahead. Let us know how it turns out, okay? |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 17060 Registered: May-04 | . "I guess I'll be getting around to whipping out some calculations "Jan Vigne". The sub that I want to get was through parts express so calling them would be a good start (probably e-mailing is better). When I gather up all the details about my speakers and subs, Ill post you back." From what Julien posts it seems obvious he's going to look into the issues of woofer replacement before he proceeds. At least, that's how I read it. . |
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Bronze Member Username: JodavisToronto, Ontario Canada Post Number: 40 Registered: Apr-09 | superjazzy, im taking in points dont get me wrong. i haven't even started anything yet with my installation plan. i've took in what "jan b vigne" had to offer me and before i went off to leave for work i actually called up a speaker shop in my city, besides parts express. to be safe his recommendation was to bring in only one speaker out of the pair and he'll have a look of what can be done as he carries many subs that might even be closely suitable. however as soon as i told him i had cerwin vega d-9s, he immediately said there are definitely a few open doors to a bigger subwoofer installation due to the monstrous size of the d9's enclosure. however, no matter what, internal bracing will be required because without it, some flexing will occure from more pressure. so im not ignoring anybody here, let me call around and if there is a good work out, ill try it and will keep you guys posted. its just that darn cash for amps that get me. |
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Gold Member Username: SuperjazzyjamesPost Number: 1790 Registered: Oct-10 | Okay then Julien, you're on a better path than the one you started on. You may want to ask this gent helping you for advice on suitable amplification for these speakers. Like Jan said, 100 watts per channel with these speakers will be enough to damage your hearing. This guy might be able to recommend something reasonably priced that will be a good mach for your speakers. |
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Gold Member Username: MagfanUSA Post Number: 2662 Registered: Oct-07 | nobody up for a refoam? That would be the most 'cost effective' way to return the speakers to nearly original condition. Unless we've already succeeded in frying a voice coil. Extra $$ could be saved towards a sub....I'm guessing Julien is a bass head who likes it loud. |
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Gold Member Username: SuperjazzyjamesPost Number: 1793 Registered: Oct-10 | If it were me Leo, I would refoam speakers I cared about, but apparently, Julien has no intention of doing so. |
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