8" sub cabinet
Printed From: Speakerplans.com
Category: Plans
Forum Name: Ported Enclosures
Forum Description: Post all your reflex and bandpass and 'other' boxes with holes in stuff here...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=97865
Printed Date: 20 April 2024 at 1:10pm
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: 8" sub cabinet
Posted By: Padde298
Subject: 8" sub cabinet
Date Posted: 21 February 2017 at 2:39pm
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Hi Guys. I am working on a "SONOS-Killer" project, and have come to the subwoofer part of the project. I have 2 pcs 8 inch units for the job. Is there any chance there is a plan for a compact enclosure, ported, bandpass or the like that will fit my project? All suggestions are welcome!  Just remember that the "wife factor"  is in play, so "the smaller the better"! (I know it poses dificulties getting bass from a small cabinet, but isn't the life all about finding solutions?)
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Replies:
Posted By: bass*en*mass
Date Posted: 21 February 2017 at 6:02pm
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without knowing your particular drivers TSP no one could recommend anything.. |
Posted By: Padde298
Date Posted: 21 February 2017 at 8:48pm
| They are Vifa M22WR-19-04, 4 ohms, long stroke units. I have the pdf data sheet, but don't see how to attach it to this post... |
Posted By: Padde298
Date Posted: 21 February 2017 at 8:54pm
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Vas 20 ltr Qms 3,44 Qes 0,87 Qts 0,70 Eff cone area 224 cm2 VC induc. 0,9 mH Free air res 48 Hz VC resis 3,2 ohms |
Posted By: Padde298
Date Posted: 22 February 2017 at 7:43am
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Updating the post with T/S data... ------------- LOUDER!!! MO BASS |
Posted By: Padde298
Date Posted: 22 February 2017 at 7:47am
 ------------- LOUDER!!! MO BASS |
Posted By: concept-10
Date Posted: 22 February 2017 at 9:06am
| http://www.speakerplans.com/index.php?id=faq1%20" rel="nofollow - http://www.speakerplans.com/index.php?id=faq1 |
Posted By: Padde298
Date Posted: 22 February 2017 at 9:54am
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Thanks for the reply, but the link is bad... ------------- LOUDER!!! MO BASS |
Posted By: Padde298
Date Posted: 22 February 2017 at 9:55am
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Oh, got it... Had to delete the "%20"... That's a lot of text... Was hoping for a more specific concrete suggestion for an enclosure------------- LOUDER!!! MO BASS |
Posted By: cravings
Date Posted: 22 February 2017 at 10:06am
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http://www.speakerplans.com/index.php?id=faq1" rel="nofollow - http://www.speakerplans.com/index.php?id=faq1 it opened badly for me too.. but it's the first FAQ there.. easy to get to. |
Posted By: concept-10
Date Posted: 22 February 2017 at 10:29am
| Watch out for drivers with really high Qts values of 0.6 or above, these would require such a big box to work correctly that in normal size boxes you don�t get much low end. They are better of being used on the rear parcel shelf of your car, where they can enjoy a massive rear chamber |
Posted By: JonB67
Date Posted: 22 February 2017 at 10:30am
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Hi padde. I'm a novice here too so here's what I had to learn: Either there is a plan for that driver, or you can build your own or mod an existing plan to suit. If you want to build a cabinet specific to that driver the best thing to do is download a programme called winISD. Google how to input the ts parameters. Open two or three projects in winISD and mess about with the box size and tuning frequency until you get an idea what looks good. Then come back and once people see you're serious they'll help you make sure your cone excursion and vent mach are ok. |
Posted By: Padde298
Date Posted: 22 February 2017 at 11:37am
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Hi Jon. Have tried to feed the T/S data into winISD, but somehow the program will not accept my Vas, Qms, Qes and Qts data, and HELP is not working either... Well, guess I'll have to investigate more later tonight (when not at job).  ------------- LOUDER!!! MO BASS |
Posted By: DMorison
Date Posted: 22 February 2017 at 12:45pm
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Anything you do with that driver is going to result in a big cabinet. To stay approximately flat in a sealed enclosure you need at least 70l of internal volume, and it will start rolling off below about 50 Hz (in half-space - in a smaller livingroom type situation you may get some "room gain" which mitigates that a bit. If you wanted to go with a vented cabinet it would need to be even bigger to avoid having a large hump in the response which is unlikely to sound good - especially if exaggerated by room gain.
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Posted By: Padde298
Date Posted: 22 February 2017 at 1:34pm
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@DMorison: I appreciate your feed back to my post! What do you base your statements on? Which factor is the cause to the problems in using the drivers in a smaller (not big) enclosure? Just so I can look for a better alternative for my project. Beeing new in the matter of calculating subs, I was of the impression that there was pre-calculated cabinets of a certain volume with a port that was tuned to a certain fq given the volume of the cabinet. I may be mistaken in this point of view? I understand that the driver in any enclusure is the basis of the performance, and if the driver can not produce the fq that is the basis of the port/volume, one is presented with a problem... ------------- LOUDER!!! MO BASS |
Posted By: concept-10
Date Posted: 22 February 2017 at 2:16pm
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I posted it for you, your qts parameter is .7 wich means it will need a big box to go low. Watch out for drivers with really high Qts values of 0.6 or above, these would require such a big box to work correctly that in normal size boxes you don�t get much low end. They are better of being used on the rear parcel shelf of your car, where they can enjoy a massive rear chamber,
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Posted By: Padde298
Date Posted: 22 February 2017 at 3:20pm
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OK, got it! I will be looking for other drivers to complete my quest for a SONOS like sub. The tops are nearly sorted. Being made of a 1" soft dome, a 3" bas/mid and a 3" slave. Being an active speaker it also has a SMPS, a class D amp and a Chromecast Audio solution. Here is the 3D construction of the top so far..: (I will be posting pictures also a little later)   ------------- LOUDER!!! MO BASS |
Posted By: Padde298
Date Posted: 22 February 2017 at 3:26pm
Pictures of the 3D printed front with frivers mounted...:   ------------- LOUDER!!! MO BASS |
Posted By: Padde298
Date Posted: 22 February 2017 at 3:29pm
Another take on the top, with same configuration:  ------------- LOUDER!!! MO BASS |
Posted By: Padde298
Date Posted: 23 February 2017 at 10:02am
Working on the finish of the tops..:  ------------- LOUDER!!! MO BASS |
Posted By: odc04r
Date Posted: 23 February 2017 at 10:20am
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Well that is certainly a fun looking project and a break from the norm of rectangular boxes. Maybe I should start thinking about stealing work's 3D printer on weekends |
Posted By: Padde298
Date Posted: 23 February 2017 at 10:43am
Everybody can build square boxes, and God knows the web is filled with them! I'm trying to design a loudspeaker system which not just sounds good, but also look interesting! Having a 3D printer at hand certainly helps when the goal is like mine... In my scope is also the possibility of fitting some kind of LED "bling" using an Arduino. But more on that later.  ------------- LOUDER!!! MO BASS |
odc04r wrote:Posted By: odc04r
Date Posted: 23 February 2017 at 11:32am
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Haha, well I would stay away from LED bling myself as a personal preference but for sure there are probably some interesting things you could do with micro-controllers. Maybe something tasteful like ambient lighting in the ports of an enclosure would be interesting as opposed to strobing LEDs in your face. |
Posted By: Padde298
Date Posted: 23 February 2017 at 1:25pm
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Being from Denmark "subtle-ness" is key... So rest asure that it will not be "in your face", but more like accent lighting... ------------- LOUDER!!! MO BASS |
Posted By: Elliot Thompson
Date Posted: 23 February 2017 at 6:53pm
Having aesthetic designs are popular in the High-End (Not Audiophile) Audio Market. Best Regards, ------------- Elliot Thompson |
Posted By: Padde298
Date Posted: 23 February 2017 at 7:02pm
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Don't know how to interpret your post... So if you care about the design of your system, you probably don't care much for the sound quality..? On the other hand, as long as it sounds good, the looks doesn't matter..? If this is your opinion, I clearly doesn't agree... I hope to have got your message wrong. ------------- LOUDER!!! MO BASS |
Posted By: Elliot Thompson
Date Posted: 24 February 2017 at 1:51am
High End Audio focuses on an exotic look with good sound quality. Your design follows the same principal. Take gander yourself https://www.higherfi.com/speakers?page=all" rel="nofollow - https://www.higherfi.com/speakers?page=all The majority of us are in sound reinforcement. Durability when the loudspeaker is being tossed in a vehicle and transported to various venues holds more value to us secondly, to sound quality. We have to take into consideration the enclosure may drop down a flight of stairs by slippery hands. In addition to what is stated previously, the cabinets need to meet certain dimensions when placing multiple loudspeakers in a vehicle for transport. Best Regards, ------------- Elliot Thompson |
Posted By: Padde298
Date Posted: 24 February 2017 at 5:23am
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OK,I get your point. Speakerplans.com is of course a PA focused forum... Seen from this fact, your initial statement suddenly makes sense to me.  ------------- LOUDER!!! MO BASS |
Posted By: odc04r
Date Posted: 24 February 2017 at 11:54am
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I'd say that high end gear focuses on looks simply to differentiate the product from the competition and partly justify the product price tags. It's a lot harder to compete in terms of engineering in that market, in many ways audio engineering has not moved on a lot in the last few decades. Most of the advances have come in areas that don't benefit the home listener much as they do not need the SPL or efficiency. So you must set your product apart in another way, and if that actually helps reduce cabinet resonances or makes them cheaper to fabricate then so much the better at the same time. |
Posted By: Padde298
Date Posted: 28 February 2017 at 10:45am
The tops are slowly coming along as to finish. The mounting of the Chromecast Audio, the 230 to 5 volt module (for the Chromecast), the SMPS and the class D TPA3118 PBTL Mono Digital Audio Amplifier..:    ------------- LOUDER!!! MO BASS |
Posted By: audiomik
Date Posted: 28 February 2017 at 11:39am
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re: "I am working on a "SONOS-Killer" project, and have come to the subwoofer part of the project. I have 2 pcs 8 inch units for the job. Is there any chance there is a plan for a compact enclosure, ported, bandpass or the like that will fit my project?" Have you considered an IB enclosure with Linquitz compensation for extended Bass frequency output? Yhis will certainly meet your request for a compact enclosure. WinISD will provide you with the filter correction graph andn you don't get the attendant phase shifts as with ported designs Mik ------------- Warning! May contain Nuts plus springs, washers, screws, etc, etc. |
Posted By: Padde298
Date Posted: 28 February 2017 at 11:47am
IB enclosure..? Please DO explain... BR Peter ------------- LOUDER!!! MO BASS |
Posted By: audiomik
Date Posted: 28 February 2017 at 12:03pm
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look up "Linkwitz Transform" using a search engine as there is considerable information on this all over the internet and much better than I can describe. Mik ------------- Warning! May contain Nuts plus springs, washers, screws, etc, etc. |
Posted By: odc04r
Date Posted: 28 February 2017 at 12:11pm
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IB = infinite baffle, Linkwitz compensation = rising low pass boost to offset driver SPL falloff mounted in such a way Tops look like nice work, how are you going to implement a crossover considering you have one mono board per enclosure - passives? |
Posted By: Padde298
Date Posted: 28 February 2017 at 12:28pm
Yes, passive. The 3" mid/bas will roll off by it self, and a simple 6 dB/oct for the 1" dome. I have done quite a few listening test with this x-over, and it seems to me that a x-over point of app. 2.500 Hz for the dome will work good. The 3" slave works fine in this size enclosure. The earlier versions was done in a smaller cabinet, which caused the slave unit to "overload". I have the miniDSP UMIK-1, but have not made any measurements in Room EQ Wizard for this combination yet. I'm a KISS kind of guy, and if it sounds good it's probably not all wrong...
------------- LOUDER!!! MO BASS |
Posted By: Padde298
Date Posted: 28 February 2017 at 12:35pm
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Is it possible to buy a circuit board for making a Linkwitz compensation? I realize that the components are given by the calculation for the driver, but getting hands on the finished board would certainly help in the process. Does it work with infinite baffles only, or can it be done with ported and sealed also? ------------- LOUDER!!! MO BASS |
Posted By: odc04r
Date Posted: 28 February 2017 at 2:04pm
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You can implement it with any cabinet, it is just a question of implementing the filter boost to be the inverse of the cabinets natural roll off. In a sealed cab this will be slower roll off than a ported cab below resonance. It is a lot easier to implement in a sealed cab as driver and cabinet combine to give one resonant peak as opposed to 2, and that resonance is what you would tune the filter to. Rod Elliott offers a project based on for sealed subwoofer equalisation I think, and would probably sell PCBs too as he does for quite a few of his pages. It is just active low pass filter using an op amp with 0db gain in the rest of the passband. The downside to this technique is that your driver is going to have very large excursion at the lower frequencies. So this is a technique normally used with sealed subwoofers capable of large excursion but that are not intended to be used with a lot of power. So then even at the lowest frequencies the driver can take the excursion. They are also often used with a steep high pass filter set low to make sure nothing too ridiculous gets through. |
Posted By: Padde298
Date Posted: 01 March 2017 at 7:31am
A few pics of the cabinet for tests..:   ------------- LOUDER!!! MO BASS |
Posted By: audiomik
Date Posted: 01 March 2017 at 11:41am
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for Linquitz Transform info, try: http://sound.whsites.net/linkwitz-transform.htm" rel="nofollow - http://sound.whsites.net/linkwitz-transform.htm This will give you the basic info Mik ------------- Warning! May contain Nuts plus springs, washers, screws, etc, etc. |
Posted By: Padde298
Date Posted: 01 March 2017 at 11:44am
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Thanx... ------------- LOUDER!!! MO BASS |
Posted By: audiomik
Date Posted: 01 March 2017 at 11:52am
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Padde298 PM me if you need further info and I can reply with a phone number as I've done a number of these boxes with reasonable success Mik ------------- Warning! May contain Nuts plus springs, washers, screws, etc, etc. |
Posted By: Padde298
Date Posted: 01 March 2017 at 12:09pm
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Dear Mik. Having read some of the material, I stumble on this section, which maybe makes the use of my drivers less than suitable..: Guidelines With the explanation and examples out of the way, you might be wondering what kind of specs to look for when choosing a driver. Here are some guidelines that should help you.
My drivers are only 8", they can only handle 150 watt, Fs is relatively high: 48 Hz and the sensitivity is 85 dB... ------------- LOUDER!!! MO BASS |
Posted By: odc04r
Date Posted: 01 March 2017 at 12:58pm
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Generally it is only used for low frequencies and that usually means drivers such as the descriptions you highlight. The key is that you are using a lot of extra excursion headroom to deliver the lower performance so having as much headroom as possible helps. That is not to say you cannot use it with less than ideal drivers - as long as you understand the limitations of the technique and design properly. For example you find that your final design has closed box resonance of 200Hz, but you want to to extend down to 150Hz as that is the highest you want to crossover to the cabinet below based on listening tests. A Linkwitz transform will allow you to do that, it dies not have to extend to 10Hz. The tradeoff is always amplifier power and excursion for the extended bandwidth. A bass driver might be moving 10mm to get the same SPL at 20Hz than at 1mm for 100Hz, maybe a 200Hz driver is moving 1mm and a 150Hz signal for the same equalised enclosure is 2mm (for a given SPL). As long as that SPL is in your design specification life is good. Consider it as an option going forward once you have measured the final item and are making your next decisions about where to go. |
Posted By: Padde298
Date Posted: 01 March 2017 at 2:09pm
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It certainly makes good sense to do the equalization that the Linkwitz Transform is doing, especially when aiming for a SMALL box. As for my project, I'm in bit of a doubt as to what I have to reconsider when it comes to the amp. IF using the LT, I would think I had to step my initial choice for amp up a nudge... Here's the amp in the project so far..: http://www.ebay.com/itm/TDA7293-Digital-Audio-Amplifier-Mono-Single-Channel-AMP-Board-AC-12V-32V-100W-/282127161910?hash=item41b016da36" rel="nofollow - http://www.ebay.com/itm/TDA7293-Digital-Audio-Amplifier-Mono-Single-Channel-AMP-Board-AC-12V-32V-100W-/282127161910?hash=item41b016da36 ------------- LOUDER!!! MO BASS |
Posted By: odc04r
Date Posted: 01 March 2017 at 3:01pm
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Yeah maybe, see how it sounds and measures first of all - then consider your options. |
Posted By: audiomik
Date Posted: 01 March 2017 at 3:09pm
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Looking at your 'Speaker specification table earlier in this thread, a suitable power amplifier as in your list will be around 300 Watts, so with the 300 watts rating quoted in the 'speaker specification table, then this will be more than adequate for your proposed use. Various modules providing this are readily available as program signal should be well within this rating. As in my earlier post, something suitable should be easy to find. I would suggest that you build one channel to start with so as to try things out first. I'm sure that a modular power amplifier to deliver 300 watts into the 4 ohms load of your loudspeaker which can be fairly easily found with a suitable power supply. See the PM I will send you shortly for possible Amplifier types,,,,,, so that you are then able to set up one amplifier channel to test things. Hope this helps! Mik ------------- Warning! May contain Nuts plus springs, washers, screws, etc, etc. |
Posted By: Padde298
Date Posted: 06 March 2017 at 8:13am
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Got the first drawings for the SUB cabinet made this weekend. Getting the MDF cut to measure during the week. Assembly in the coming weekend (maybe... #wifefactor) Any comments..?   ------------- LOUDER!!! MO BASS |