malium wrote:First, hello to all diy-ers!
I really need some help with my future project. The project is a bit "off", but I hope here are some good souls willing to help.
I would like to build a pair of speakers that would give me solid performance for music listening, and for watching the movies.
Cause of the room size where they will be paced (5 x 4m), and because of the furniture setup, and overall looks of the room, I would like to have a stereo system, and not the 5.1 system.
From the same reason, I would like them to be strong on the bass area, for the movie effects (and by this to avoid using a separate woofer), but I also want to enjoy in quality music as well, so I do not want them to be boomy.
Now, my crazy "interior design idea", is to build speakers in the wall corner. To build a wooden front baffle, and "attach" it to a wall corner. Doing this would make a triangle shaped cabinet, but I would make a narrow wooden rear end that would flatten a 90°angle of the walls. So in the end, the speaker box would be shaped as a trapezoid, built from wooden front baffle with drivers, and eased concrete wall corner. This speaker boxes should be as shallow as possible, but I would have plenty space in the height, cause they would be made from floor to ceiling (about 2,5m).
My question regarding this is, is this even possible? What should I expect from boxes made like this? Should I treat the part of the walls inside of speaker somehow?
I already have some drivers laying around that I would like to use for this project.
I have four new pieces of JAMO 10" woofers with this specs (all specs that I have, they are OEM, so there is almost no info on them):
Impedance: 4 ohms
Vas: 173,9 l
Fs: 33,7 Hz
I also have four new pieces of this TVM midwoofers:
And in the end, I have four new pieces of:
http://cgi.ebay.com/NEW-1-Silk-Dome-Twe ... dZViewItem
I would like to use this drivers in this project, from the simple reason - I already have them.
I am searching for an advice on how to combine them, to use them all or some, to build separate cabinets inside the speaker box for some of the drivers, crossover ideas, any other ideas or comments...
Well, the third question is, what to use to run them after they are built? I do not have any experience on this as I was on computer 5.1 systems till now... So I do not know much on how much power would this speakers need to run fine. I am not chasing any extra high volumes, doe. I have one plate amp from Soundworks 510d, rated at 500W (150W for sub, 70W x 5 for satellites), I do not know if I can use it anyhow, or I should buy some stereo amp, receiver or something... Please advice.
I know this is a big amount of questions, and that the project is a bit off, but I would like to finish it with some of Your help. I would make a project log, and share this project with You folks.
Many, many thanks in advance,
You never really know what a speaker is going to sound like 'till you build it. But in a given price range, you can usually build a better-sounding speaker (with higher quality drivers) than you can buy.What should I expect from boxes made like this?
For designing a proper box and predicting bass response, I recommend you download a copy of WinISD (FREE!!!). (The bass response depends on the interior volume, port dimensions, and the speaker's Theile/Small parameters.) It's most important to get a good subwoofer design to prevent wimpy or boomy bass. But, it won't hurt to plug-in the numbers for your mid-woofer too.I would like them to be strong on the bass area, for the movie effects (and by this to avoid using a separate woofer), but I also want to enjoy in quality music as well, so I do not want them to be boomy.
I have one concern with the Soundworks amplifier. A "real" subwoofer should cross-over at about 80Hz. From the size of the original satellite speakers, I'd say they don't go that low and the crossover will be set to a higher frequency. Since your mid-woofers can go down to 80Hz, a home-theater receiver with a lower subwoofer crossover point would be a better option. (You can configure most HT receivers for 2.1.)Well, the third question is, what to use to run them after they are built?
This is a very reasonable thing to do. You can easily enjoy both music and movies without a center channel or subwoofers as long as you have full-range (or "large" in HT setup speak) speakers. But for full surround sound, you'll need rear speakers - something to keep in mind because if you decide to add them later, you'll want to use the same drivers you're using on the front speakers to maintain the same sound.
You can also go "small" on the front speakers and use one or more subwoofer for the overall system. Most AV receivers have bass management and can re-route the bass to a single sub just as easily as they can to "large" front speakers.
Are you implying that the corner walls of your room will be part of the speaker cabinet? or that the speaker cabinets will be placed at the corners of the room? I would not do the former; the latter is fine. Using the existing walls as part of the cab is begging for trouble as walls are never flat nor form true right angles; the walls will resonate (if wallboard); air will leak; among all sorts of other problems.
Sorry, don't know anything firsthand about these drivers. Looking at the specs - note that the JAMO are 4 ohms but the mid and tweeters are 8 ohm nominal so keep that in mind when designing your crossover. Also the midwoofers are less efficient (rated 85 dB, 1w/1m) than the tweeters (89.6 dB) so you've got work to do there. Xmax on the mid is 7mm (footnote 5 is not shown) but I'm guessing that's peak to peak and not one way. With a rated "noise" power of 60 watts I wonder how loud this driver will go. Luckily your room is not that big; but it's up to you to decide how loud you want this to play.
Take the specs on the Cambridge Soundworks system with a grain of salt as far as power goes. That said, are you happy with the volume it puts out? Can the 510d be used as just an amp by simply disconnecting those little cube speakers and sub?
If you don't or can't use the 510D, then all you really need is a simple AV receiver. You can get a decent, older, Yamaha / Denon / HK / Marantz / Onkyo on eBay for around $150 or less (depends on power, brand, shipping cost, etc.) It'll cost even less if you buy a Pioneer, Technics, Sony or other mass market brand. You'll have to do some research for individual models (flaws, features, etc) so that may take some time to iron out. Get one with the same kind of features you want (Dolby Digital or DTS for instance if you ever plan on adding rear surround speakers). Of course, you can go with a standard 2 channel receiver for cheap if sound processing is not important but you will likely lose the ability to steer your bass. My point is that since you're not gunning for fancy features, you have a wide range of choice to play with on the used market. Just make sure the unit can interface with whatever your source player is.
Another option is to get just amps, not a receiver, since your computer can do all the sound processing for you. This may be cheaper or more expensive, depending on what you buy. If you go with your original plan of just 2 channels, and you stick to 2 full-range speakers, all you need is a 2 channel amp (or receiver used as an amp). Lots of options here.
As for power, when in doubt, get more than you need and don't turn the volume up. That's better than not having enough. My first receiver was all of 25 watts per channel. I still use it today and it works great. My bet is that you'll be fine with 50 watts but why not aim for say 75 or 100 watts or more? And don't forget it's all about how efficient the speakers are, how loud they can play max, how much power you can deliver to them and how loud you want them to play. It's not all about amp power.
I think this can work!
Have you ever built a speaker before? Do you have a speaker building book? Do you know how to wire-up a crossover?
For designing a proper box and predicting bass response, I recommend you download a copy of WinISD (FREE!!!). (The bass response depends on the interior volume, port dimensions, and the speaker's Theile/Small parameters.) It's most important to get a good subwoofer design to prevent wimpy or boomy bass. But, it won't hurt to plug-in the numbers for your mid-woofer too.
When you place a woofer in a corner the bass gets boosted, and it can get boomy. So, you might have to experiment. You'll get even more boost if you place the woofer near the floor (or ceiling) where 3 walls come together.
You will need to isolate the mid-woofer from the subwoofer. You'll effectively need 2 separate boxes or a "box in a box". (I assume the tweeter has a sealed back and doesn't need to be isolated.)
It's generally a good idea to fill or line the box with fiberglass or some other acoustic "stuffing". This helps to prevent resonances, standing waves & "ringing" inside the cabinet. (The triangular shape helps with that too!)
I have one concern with the Soundworks amplifier. A "real" subwoofer should cross-over at about 80Hz. From the size of the original satellite speakers, I'd say they don't go that low and the crossover will be set to a higher frequency. Since your mid-woofers can go down to 80Hz, a home-theater receiver with a lower subwoofer crossover point would be a better option. (You can configure most HT receivers for 2.1.)
Many HT receivers are intended to drive powered/active subwoofers & they don't have a power-amplifier channel for the subwoofer. So, you might need to use the Soundworks subwoofer amp. (In this case the Soundworks internal crossover is not a problem since it's crossover frequency is higher than the receiver's, it won't have any effect.)
I'd recommend wiring the tweeter and mid-woofer with a passive crossover as a 2-way design, and then wire & drive the subwoofers separately.
Since you'll have 2 subs, 2 mid-woofers & 2 tweeters, do you know about impedance and series/parallel wiring? (Parallel wiring of 2 speakers halves impedance, & series wiring doubles impedance.) It depends on your amp, but be careful about wiring 2 the two 4-ohm subs in parallel... The 2-ohm load might blow the amp!
I do have a slight concern about the 6 ohm tweeter. Most crossovers are designed for 4 or 8 ohms. You might want to look for a crossover design program. If you connect it to a 4-ohm crossover, it will "kick in" at a lower frequency, and there will be (more) overlap between the tweeter & midrage and yo might get a "bump" in the frequency response (and an impedance dip). If you use it with an 8-ohm crossover, it will kick-in at a higher frequency and there may be a gap/dip in the frequency response between the midrange & tweeter.
As far as power... Well, speaker power ratings are often suspect and it gets tricky... You can burn-out most tweeters with an average amplifier & test tones. But, one rule-of-thumb is that you can use an amp with twice the power rating of the speaker, with normal music, as long as you don't drive the amp into distortion. With music instrument amps (i.e. guitar amps), which are often driven into distortion, the rule is reversed... Use speakers with twice the power rating of the amp.
Any "average" receiver with 75-100W per channel is OK with most "average" speakers as long as you use the system for normal listening. If you have parties with loud-distorted music, you're in the danger zone unless you're using heavy-duty PA speakers.
The thing is... Music is unpredictable. Every song has different frequency-power distribution, and every song has a different peak power to average power ratio. We could be absolutely safe by using high-power pro PA type speakers, or by using a way-underpowered amplifier. But, most people get by safely just by not driving their speakers into distortion.
Worst case.... You burn-out a driver. You built the system and you can easily replace the driver with a higher-power unit!
I think this is fine.Yes, my idea was that the wall corners of my room be a part of the speaker cabinets. I do not think they will resonate because they are made from concrete?
Right.I would connect them in series. Then they should act as one 8 ohm unit? Right?
A perfect speaker would have a flat frequency response curve. The basic idea is to design the cabinet so that the bass extends as low as possible and to avoid any big resonance bumps that will make the speaker sound boomy. (You probably don't want any peaks/bumps greater than +3dB.)have already downloaded a WinISD, but I have to download something that will explain me the results I am getting...
The voltage from the amp is "constant" (it doesn't change when you change impedance). Two speakers in parallel will play louder than one speaker (+3db), since both speakers are getting the same voltage/power. Two speakers in series will play quieter than one speaker (-3dB) since the voltage is split between the two speakers (and given the same total voltage, you get less total current/power with the higher total impedance). And of course, two speakers can handle twice the total power as one speaker.I am not sure should I use one ore two tweeters for one speaker. Is there any gain from using two tweeters?
I may bave built a crossover once, but I usually just buy one. Since most of us home builders don't have anechoic chambers and all of the equipment to properly test a speaker, I've never considered using an "advanced" crossover designs.I can build a crossover, but I do not understand them completely.
Probably not a good idea. You might be able to set the rear outputs to be the same as the fronts, but the settings would get messed-up at some point and I'd say it's not worth it. And, 100W should be plenty.If I use a budget AV receiver that I have (Pioneer VSX-416), I could only get use of two amp outputs (front - 2 x 100W) for running this speakers. I cannot get use the rear or center channel outputs for getting some additional W?
There's a LOT of nonsense in the audiophile community! All speakers sound different, but most amplifiers sound alike (in proper blind tests ). Look at power, noise, distortion, and frequency response, and ignore any "audiophile terminology". With modern electronics it's cheap and easy to build a low-noise, low-distortion amp with flat frequency response... Just about the only spec to worry about is POWER. For more on this, take a look at Audiophoolery by Ethan Winer. And, if you find that useful or interesting, you can watch Dr. Winer's AES Presentation on YouTube.I have read a lot regarding this, and all over the forums I see some confusing guidelines. Some people are saying that stereo power amplifiers like NAD, Rotel and so, are giving much more performance in music playback then the standard AV receivers.
From a computer? Computers often have cheap (noisy) soundcards, and in this case a digital connection is better. ( It doesn't matter if the digital S/PDIF connection is optical or electrical. Its the same digital ones zeros.)So, I am not sure, which is more? AV receiver, optically connected, or the stereo amp, analog connection?
I don't think the Rotel has a crossover or "bass management". So, you could use it for the subwoofers if you drive it with the line-level subwoofer output from the receiver.In the end, I think I found a solution, but I need You confirmation. Rotel RB-976 is a 6 x 60W amp.
malium wrote:One more question to You guys, before I start to build this monsters...
Would something like this be ok for running the woofers?
http://cgi.ebay.com/4-100-watt-4ohm-TK2 ... 3a5e69ded6
Could I use something like this to run only Jamos, while the rest would be run by the AV receiver? I would use this amps four outputs, one for each woofer, and I could connect such amp to a AV receiver subwoofer preout?
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